Here's a long-winded post about the Dual and the Square, based on my experience. If you don't want to read the details, here's the short version: I like both, and they serve different purposes.
Now the details:
I have a Dual V3 (actually I have 2 of them) and now the Haze Square (phase 1).
They are very different vapes. Comparing them is a bit like comparing apples and oranges.
The Dual is a session vape, with a hybrid type system. I prefer using the cans, so what I get is a lot of conduction and a bit of convection. The result is a nice, steady vape session that lasts quite a long time. I find the Dual very easy to fill and clean, and I get reliable vapor from any material. I really don't have to think about it much, it's just easy and convenient and handles whatever I put into it.
The Dual did have problems at launch (I was there) but with the V3 it's now very nicely designed. The Dual still has one big flaw in my opinion -- if you use very resinous material, or (even worse) concentrates, you will eventually get build-up on the outside of the inner shaft. This build-up cannot be cleaned without disassembling the unit (and killing your warranty). I've done this with one of my units, and it's actually not that hard to clean and restore to perfect, but of course Haze isn't going to officially support anyone pulling the unit apart. You're supposed to send it in for "deep cleaning". Anyway...enough on that.
The Square is a convection vape, and it's an excellent one. But the on-demand nature, and the very open air flow design, means you have to learn to use it. Everything affects the outcome -- material selection (how fine the grind, how damp, the strain, etc.), amount, how hard you tamp it down, how fast you draw, how long you hold the button, how high you have the temperature, how *clean* your screens are (this is vital!), and so on.
You get the idea. The Square requires a bit of experience and experimentation (at least it sure did for me!). It will never be as easy to use as the Dual.
However, the Square produces the *most* tasty and amazing hits I've ever encountered, anywhere. And it hits really hard. It's worth having around just for that experience.
The battery life is poor if you're an all-day user like me, but the Square isn't really designed for that, in my opinion. It's an on-demand device that'll give you a powerful effect right away. I charge it after every 2 bowls, and it takes about 15-20 mins on the wall charger.
Finish-wise, my Square is ok (it's a phase 1). Not amazing, it looks a bit rough, and it's very easy to scuff. But then again you should see my Dual. It's got the finish all rubbed off in place and scratches, etc. Both units are solid and functional, though.
I'm a bit worried that the main switch on the Square will fail -- I've already had it stick in the depressed position a couple of times, but wiggling it freed it up...time will tell.
I mentioned cleaning -- the Square needs to be *very* clean. I find that performance suffers after just a couple of bowls through those screens. They don't look very dirty, but it matters. Until I started cleaning it completely, I was getting inconsistent results and I had to use higher temps. I bought an extra set just so I could always have clean ones on hand.
Cleaning the Square is easy enough, but you also have to do it a lot. I do like that you can clean everything completely -- the entire air path. I won't have to disassemble the Square
The Square goes through material a lot faster -- those big bowls are part of it, I suppose, and no doubt it's the reason the Square hits so hard -- but it's a factor to consider. I estimate I use 3 times as much material in a day of Square usage compared to the Dual. I'm also more medicated, but oddly enough it wears off sooner.
The Square has not replaced the Dual, for me. It has become a welcome addition, instead.
I still like the Dual for my usual session vaping -- puffing at it while I do other things, I don't have to think much, don't have to worry about draw or holding down a button for the right length of time. It's also great for having next to the bed for those occasional insomnia nights.
But I also fill up the Square in the morning, and grab it whenever I want an immediate boost. I find that the two vapes complement each other very well.
My phase 2 should be delivered tomorrow. Will post pics of those spots for all. Still stoked for it to get here!!