30-Second Verdict
The Solo 3 v2 wins, and it isn't close on the numbers — 9.2 against 8.3. The honest truth in one line: the Solo 3 v2 is the better vaporiser, and the PAX 4 is the better thing to have in your pocket, and those are genuinely different jobs.
Solo 3 v2: 9.2/10
PAX 4: 8.3/10
Buy the PAX 4 if:
- The device has to live in a jeans pocket and read as generic consumer tech
- You want zero learning curve — one button, four modes, done
- You're buying the way you'd buy a nice watch: design first, spec sheet second
- Your sessions happen out of the house more often than in it
Buy the Solo 3 v2 if:
- Flavour is the reason you vape rather than a nice bonus
- You want session AND on-demand in one body
- Most of your bowls happen at home, on a desk, on a sofa
- You'd rather clean a glass stem in thirty seconds than a screen every week
Quick Specs Face-Off:
| PAX 4 | Solo 3 v2 | |
|---|---|---|
| Heat-up | ~20s | ~20s session / ~15s on-demand |
| Battery | Sealed 2800mAh, ~5 sessions | Sealed, 12–15 bowls |
| Bowl | ~0.35g (half-pack lid included) | 0.1–0.15g glass stem |
| Weight | 125g | 280g |
| Warranty | 2yr, 3 with registration | Lifetime heater / 2yr device / 1yr battery |
| Price | Check current price | Check current price |
The Hook: The Tailored Suit and the Walking Boots
There are two things by my front door that I would defend to the death, and they have nothing in common.
One is a suit. Proper one, fitted, the only garment I own that makes me look like someone who files his taxes early. It comes out for weddings, interviews, and the occasional restaurant where the menu doesn't have prices on it. It is useless in rain. Worse than useless up a hill. But when the situation calls for it, nothing else in the wardrobe is in the conversation.
The other is a pair of walking boots. Scuffed, re-waterproofed twice, moulded to my feet through years of Peak District weekends and one regrettable attempt at Kinder Scout in horizontal sleet. They are not attractive. But they are built for the actual weather — the real, wet, uneven world — and every time it matters, they're the ones on my feet.
The PAX 4 is the suit. The Solo 3 v2 is the boots.
I called the PAX 4 the Smeg toaster of vaporisers in its review — the object you buy for how it sits on the counter, that also happens to toast bread with composure. I called the Solo 3 v2 Joy Division becoming New Order — the flavour benchmark that finally got its software finished. Both of those hold. But put them head to head and the frame changes, because you're no longer asking "is this good?" You're asking "which one do I actually put on today?" — and the answer depends entirely on where you're going.
One of these dresses well in public. The other is built for the terrain. The mistake — the expensive, common mistake — is buying the suit for a hike, or the boots for a wedding.
We stock both at HerbVape.co.uk — details and pricing below.
Vapour Quality
Solo 3 v2: 9.5/10. PAX 4: 7.8/10. The Solo wins, comfortably, and nobody sensible disputes it.
That 1.7-point gap is the biggest single spread in this comparison. The Solo 3 v2's all-glass path produces terp clarity I described in its review as vinyl versus streaming — the same song, but you keep noticing notes you didn't know were there. Its hybrid heater runs roughly 80% convection to 20% conduction, and it does session mode and on-demand mode from the same body.
The PAX 4 is the best non-Flow PAX ever made, which is genuine praise with a ceiling built into it. It's conduction-leaning. It sips, it doesn't rip: four to six properly flavoured draws on Mode 2 if you treat it like a cigar, a mouthful of warm air if you treat it like a bong. The 3D oven screen has fixed the hot spots, and the vapour is clean and slightly compressed — terps in concentrated form rather than expansive form. Good vapour. Not great vapour. The PAX 4 review said exactly that and I stand by it.
The fair framing: the PAX 4 no longer needs an apology, which is a real achievement for the brand. But the Solo 3 v2 doesn't just beat it — it's playing a different sport. If vapour quality is your first question, this comparison is already over. The rest of the article is about why it might not be your first question.
The Strain Test, Side by Side
Same two jars, same grinder, every device on this site. That's the whole point of the control: when the flower can't vary, the machine has nowhere to hide. Both of these got the full protocol in their own reviews — the PAX 4 nudged onto 180/193/205°C with its manual adjustment, the Solo 3 v2 stepped through 175/185/200°C in session mode — so we can put the findings directly alongside each other.
Jack Herer
Jack is the strain that shows you up: terpinolene-led, fragile top notes, pine and lemon peel that vanish the moment a device can't hold them.
On the Solo 3 v2, the pine needles arrive on draw one with nothing in front of them — no warm-up note, nothing the path has added — plus a cooling menthol edge I only ever get off a cold glass stem. The citrus lift doesn't die at mid-temp; it thins gradually across three draws while black pepper takes over, and even at 200°C there's still pepper distinguishable from heat. Fourteen legible draws. I called it the best Jack Herer I get from anything that doesn't plug into a wall — not the loudest, the most legible.
On the PAX 4, draw one is better than any PAX has ever given me — proper pine, proper lemon peel, actually the strain rather than a suggestion of it. Then the oven walls catch up. By draw three the citrus lift has thinned to general green-herb warmth; by draw five the pine is a memory. Where the Solo 3 lets the pine hand over to the pepper in stages, the PAX 4 blends them — pepper and wood arriving together rather than stacked, which is the conduction tax and there's no engineering around it at this price.
Side by side: the Solo 3 stretches Jack's fragile top end across five draws; the PAX 4 gets two and a half good ones before the hot walls sand the top off. Both reviews said this in their own words. Put them in the same sentence and the gap is stark — the PAX gives you a recognisable Jack, the Solo gives you a resolved one.
Wedding Cake
Where Jack exposes a device, Wedding Cake flatters it — caryophyllene-first dessert genetics, vanilla and cream over sweet dough, built low and heavy.
On the PAX 4, this is the best thing the device does. At 193°C, butter turns up alongside the vanilla rather than replacing it, warm dough behind both, pepper emerging late without flattening anything — four things I could name separately, which is more resolution than a conduction oven at this price has any right to deliver. It's the single strongest argument for the PAX 4's 7.8 vapour score. The review called it a dessert-strain machine and it is.
On the Solo 3 v2, the same four components arrive nameable — vanilla, butter, dough, pepper — but from the low stage onwards, and cleaner throughout. Cherry deepening towards jam on the exhale at 185°C. The one honest concession the Solo makes: glass doesn't upholster. The rendering is well-lit and faintly clinical where a cooling unit would add plushness — brighter and more precise, a bit less warm-blooded.
Side by side: on this jar the fight is closer than the scores suggest. The PAX 4's best moment — the 193°C separation — genuinely belongs in the same conversation as the Solo's mid-temp stage. The difference is the range either side of it. The Solo does that trick on both strains, at every stage; the PAX does it on one strain, at one stage, and by 205°C both jars have converged into the same brown roast.
The call: the Solo 3 v2 is a flavour device, full stop — both strains still read as two different plants at the top of the range. The PAX 4 is half and half: a flavour device for dessert genetics, a delivery device for everything fragile. That's exactly the split its own review landed on, and the head-to-head confirms it.
Design & Build
Two very different definitions of "well made." The PAX 4 is anodised aluminium machined to obsessive tolerances — no visible screws, no seams, the prettiest vape in its class and possibly in the shop. Sarah held the Sage Green unit for thirty seconds before asking what it was. It scored 9.5 and earned it. The one flag: the grip warms during long top-mode sessions, and the silicone sleeve really should be in the box at this price.
The Solo 3 v2 is chunky Arizer solidity — 280g of anodised aluminium that has survived eight months of daily use and multiple tumbles without a rattle or a dead pixel. It scored 9. The vulnerability isn't the body, it's the glass: I've cracked two stems in eight months (tiles, mostly), and you budget for spares the way you budget for printer ink.
Winner: PAX 4, narrowly — as an object, it's the suit, and nothing Arizer makes hangs like it. As a survivor, honours even, with the asterisk that only one of these has a wardrobe of breakable glass accessories.
Battery & Charging
Not close. The Solo 3 v2 does 12–15 bowls per charge at normal temps, supports pass-through, and refills over USB-C PD in about ninety minutes with a proper brick (Arizer quotes three hours; expect the ninety). The PAX 4 does about five sessions, charges in roughly 100 minutes, and has no pass-through party trick to lean on.
Both batteries are sealed, and both reviews made the same point about it: 18–24 months of daily use puts you on the degradation curve with no user-swappable fix. The Solo's mitigation is that its bigger tank means fewer cycles for the same usage. The PAX's mitigation is the 50%-in-25-minutes top-up while you eat dinner before going out — which, to be fair, matches how the device actually gets used.
Winner: Solo 3 v2, by a distance. Triple the bowls, faster practical charging, pass-through. The PAX 4's 7.5 against the Solo's 9 is one of the fairest score gaps on the site.
Ease of Use
The PAX 4's home territory. One button, four modes, haptic feedback, lip-sensing, twenty-second heat-up, and genuinely nothing to learn — you don't learn the PAX, you just use it. It scored 9.5 and it's the strongest single argument for choosing it over the Solo.
The Solo 3 v2 scored 8.5, and the missing point is real: session mode is simple, but on-demand mode has an honest learning curve. Overpack it and the first press browns the top layer — I did it myself in week one. Pack loose, leave 2–3mm headroom, and it behaves forever after, but "behaves after you've read the quick-start guide" is a different promise from "behaves before you've opened the box."
Winner: PAX 4. If you want the device your least technical mate can use unsupervised on day one, it's the PAX, and it isn't particularly close.
Cleaning & Maintenance
Different philosophies. The Solo 3 v2's glass stems are the only parts that gunk up — the oven stays essentially new because the herb sits in the stem, not the chamber. Thirty seconds of routine care, an ISO soak every 10–15 bowls, done. It scored 9.5, the best on the site short of a DynaVap.
The PAX 4 is the best-cleaning PAX yet — magnetic mouthpiece, pop-out 3D screen, accessible airpath, no tools — and still scored a point lower at 8.5, because the frequency is the tax. High-frequency-low-effort: skip the weekly clean and the vapour goes flat and resin-y within two or three sessions. The PAX cleaning kit stops you improvising with stationery.
Winner: Solo 3 v2. Less often, less effort, and the reclaim in the stems is actually usable.
Portability
The entire reason this comparison exists. The PAX 4 is 125g, the size of a roll of mints, and disappears into a jeans pocket reading as generic consumer tech. The Northern Quarter Friday test from its review — front pocket, no case, used twice, clocked by nobody — is the use case in one sentence. It scored 9.5.
The Solo 3 v2 is 280g and 49mm across. It fits a jacket pocket with intent, needs a case for its glass, and produces visible vapour that isn't fooling anyone. It scored 7, and its own review was honest enough to call it an "around the house" portable and stop pretending otherwise.
Sarah watched me try to take the Solo out one Friday, jacket sagging on one side, and said, "You look like you're smuggling a thermos." I took the PAX.
Winner: PAX 4, in a landslide. This is the one category where the 9.2 device gets properly beaten, and it's the category the whole buying decision hangs on.
Value for Money
The Solo 3 v2 scored 9 on value; the PAX 4 scored 7. The price gap between them buys you a 1.7-point vapour upgrade, triple the battery, easier cleaning, and a second operating mode — which, priced per point, makes the Solo one of the best deals on the site and led its review to call it the best value-per-quality ratio in the £200–300 bracket.
The PAX 4's value case was never going to win a spreadsheet fight — its own review conceded it loses to the V3 Pro, the Smono 4 Pro and the Solo 3 v2 on pure maths. What the PAX 4's money buys is design, pocketability, warranty cover and the easiest user experience in the bracket. That's the Smeg argument, and it's a real argument — it's just not a value argument.
Winner: Solo 3 v2. Paying more and getting more per pound is a rare trick, and the Solo pulls it off.
Score Comparison
| Category | PAX 4 | Solo 3 v2 |
|---|---|---|
| Vapour Quality | 7.8/10 | 9.5/10 |
| Design & Build | 9.5/10 | 9/10 |
| Battery & Charging | 7.5/10 | 9/10 |
| Ease of Use | 9.5/10 | 8.5/10 |
| Cleaning & Maintenance | 8.5/10 | 9.5/10 |
| Portability | 9.5/10 | 7/10 |
| Value for Money | 7/10 | 9/10 |
| Overall | 8.3/10 | 9.2/10 |
Three category wins for the PAX 4 — design, ease of use, portability. Four for the Solo 3 v2 — vapour, battery, cleaning, value. The Solo's wins are the ones that decide whether you keep using a vape. The PAX's wins are the ones that decide whether you take it anywhere.
Who Should Buy Which
Buy the Solo 3 v2 if your vaping life happens mostly indoors and flavour is the point. If you're the person who steps temperatures, who wants an on-demand hit between work tasks and a long session in the evening from the same device — the Solo is barely a decision. Medical users get the extra argument of precise, repeatable extraction and a battery that won't quit mid-week.
Buy the PAX 4 if the vaporiser needs to leave the house more often than you do. If your sessions happen at gigs, in beer gardens, between courses, on walks — places where a 280g cylinder with a glass stem is a liability and a matte pebble that reads as an iPod is exactly right. Buy it too if you're the person the ease-of-use score was written for: no technique, no headroom rules, no stems to soak. And buy it, honestly, if you just want the pretty one. That was a defensible reason in the PAX 4 review and it's defensible here.
The genuinely wrong purchases are the crossovers: the PAX 4 as your only at-home daily driver (you'll feel the vapour ceiling within a month), or the Solo 3 v2 as your going-out vape (you'll feel the weight within a week).
How I Actually Choose
Both of these are in my rotation right now, and the split is embarrassingly clean.
The Solo 3 v2 lives on my desk — the Sea of Green unit, roughly 35% of everything I vape, the biggest share in the collection. Session mode most evenings for pain management, on-demand between work tasks: press, two draws, back to the spreadsheet. It's the device that broke my kettle ritual, which its review covers in full and which I'm still slightly bitter about.
The PAX 4 holds the pocket slot — three or four sessions a week, Mode 2, half-pack lid, going-out duty alongside the Flow. Pubs, gigs, dinners, the Friday nights the Solo physically cannot come on. Sarah has attempted to annex it twice, which is more interest than she has ever shown in anything Arizer makes.
Notice what neither device does: replace the other. In eight months of owning both, the number of times I've reached for the PAX at home is roughly zero, and the number of times I've pocketed the Solo for a night out is exactly one (see: thermos).
The Verdict (The Bookend)
You don't wear walking boots to a wedding, and you don't climb Kinder Scout in a suit.
The Solo 3 v2 is the better vaporiser. The scores say it, the strain test says it, and the price gap doesn't come close to closing the quality gap — if anything the Solo widens it on value. If you are buying one device to be your main device, buy the Solo 3 v2 and don't lose a minute of sleep.
But "better vaporiser" and "right purchase" are only the same thing if you vape where the Solo lives. The PAX 4 exists for the part of your life the Solo can't attend — and it does that job with more composure than anything else in the shop. The suit doesn't need to be waterproof. It needs to be the thing you're glad you own on the three nights a month that matter.
Most people should buy the boots. Some people genuinely need the suit. The lucky ones — and I say this as a man with both by the door — eventually own the pair.
FAQ
PAX 4 vs Solo 3 v2 — which should I buy?
The Solo 3 v2 if vapour quality, flavour, battery life or value lead your decision — it wins all four, 9.2 to 8.3 overall. The PAX 4 only if pocketability and simplicity lead it — but if they do, it wins those outright. The honest question is just whether you need a pocket.
Is the Solo 3 v2 really that much better on flavour?
Yes. The all-glass path holds Jack Herer's fragile top notes across five draws where the PAX 4's conduction oven manages two and a half. On dessert strains like Wedding Cake the gap narrows considerably — the PAX 4's 193°C separation is genuinely impressive — but the Solo does it at every temperature, on every strain.
Which has the better battery?
The Solo 3 v2, decisively: 12–15 bowls per charge against the PAX 4's ~5 sessions, plus pass-through and a ~90-minute PD refill. Both are sealed, so both are on an 18–24-month degradation timeline for daily users — the Solo just cycles less often for the same use.
Which is easier to clean?
Different shapes of easy. The Solo is thirty seconds of stem care with an ISO soak every 10–15 bowls; the PAX 4 is a quick but weekly screen-and-airpath routine. The Solo wins overall — but the PAX 4 is the best-cleaning PAX ever made, for what that's worth.
Can I use either with a bong or water piece?
The PAX 4's Mode 4 (220°C) works well through a water piece at home, and that's my preferred way to run it at the top mode. The Solo 3 v2's glass ecosystem includes water-pipe adapter stems, and being Arizer glass, your existing Solo 2 or Air MAX accessories carry over.
Is the PAX 4 worth it when the Solo costs only a bit more?
Not on performance — the Solo is better at nearly everything and better value per pound. On pocketability, yes: the Solo cannot do the PAX 4's job at any price. If you never need the pocket, save nothing and spend the difference. If you do, the PAX is the only one of the two that can come.
What about the warranties?
The Solo 3 v2: lifetime on the heater, two years on the device, one on the battery, glass excluded. The PAX 4: two years, three with registration inside 30 days — and note the old ten-year PAX warranty does not apply to this device, whatever the forums say.
About Dennis M.
Dennis M. has been vaping daily for the best part of a decade — since an original Mighty in 2018 — and has tested 50+ devices for this site. He works in IT, has ADHD, and uses cannabis for chronic pain management. He lives in Manchester with his partner Sarah, who has attempted to annex the PAX 4 twice and has never once touched the Solo 3.
He owns one suit and one pair of walking boots, and has worn the wrong one to precisely one event each — a story he will tell you in exchange for a coffee. The Solo 3 v2 broke his carefully calibrated kettle ritual and he has almost forgiven it.
A note on spelling: 'vaporizer' is the de facto international spelling, but I've stuck with the British 'vaporiser' throughout this blog.
Questions, corrections, or a device you want tested? dennis@herbvape.co.uk
Related Content
Full Reviews:
Head-to-Head Comparisons:
- PAX 4 vs PAX Flow: Which PAX Should You Buy?
- PAX 4 vs V3 Pro: Design Tax vs Spec Sheet
- Solo 3 vs Mighty+
Best-Of Guides:
New to Vaping?
Get Both at HerbVape.co.uk
Solo 3 v2 — the boots: the flavour benchmark that does session and on-demand from one body.
Buy the Solo 3 v2 →
Worth grabbing with it: Air / Solo - Screen Set — spare stems and screens, because tiles happen.
PAX 4 — the suit: the prettiest, most pocketable vape in the bracket.
Buy the PAX 4 →
Worth grabbing with it: Pax Basic Maintenance Kit — the weekly clean, without improvising with stationery.
Just one more bowl.
Last updated: 25 September 2026.
Review Policy: I buy or borrow the devices I review. HerbVape.co.uk is my employer, but my opinions are my own — they pay me to be honest, not to sell you shite. Affiliate links and discount codes exist because running a site costs money, not because they influence scores.
Strains Used: Jack Herer — sativa (Haze × Northern Lights #5 × Shiva Skunk), ~20% THC, terpinolene/caryophyllene/pinene-dominant, pine-citrus-pepper profile with fragile top notes. Wedding Cake — indica-leaning hybrid (Triangle Kush × Animal Mints, via Triangle Mints #23), ~24% THC, caryophyllene/limonene/myrcene-dominant, vanilla-cream-dough dessert profile over peppery earth. Same two strains, same jars, across every vaporiser reviewed on this site — the strain is the control, the device is the variable. Strain effects vary by individual, batch and consumption method.
Medical & Legal Disclaimer: Nothing in this article constitutes medical advice, and I am not a medical professional. Cannabis is a controlled substance in the UK; medical cannabis is legal only on prescription from a registered specialist clinic — Sapphire, Cantourage and Zerenia are three of the larger ones. HerbVape.co.uk sells vaporiser hardware only: we do not sell, prescribe, or recommend cannabis or cannabis products. Vaporisers are sold for use with legal dry herbs and legally prescribed medical cannabis. You must be 18 or over to buy one, and cannabis law varies by jurisdiction — check yours.