My feelings are biased because my MV1's (literally 5 replacements) had defects they readily replaced. But at times I got very good results before issues, e.g., overheating, took over.
That said, the FW5 gets me just as high just as quick. Maybe two FW5 chambers equals one MV1 crucibles, but I vape five FW5 chambers easily with much less fuss than two or three MV1 crucibles.
The main differences that tip the scale way in favor of the FW5 are:
1. Ease of use. The thing just works. No weird lights or heatsink seals or finicky crucibles with lids that need cleaning EVERY crucible. The FW5 design of drawing heat down (rather than up through a lid that clogs ridiculously easy) is just better. Moreover, changing heat settings takes about 2 seconds on the FW5. The MV1 is obnoxious on changing settings or getting the App to sync. Hated it on that point.
2. Cleaning. It's basically optional to clean a FW5 for a LONG TIME and it works GREAT still. The MV1 is like an annoying girlfriend that wont do anything unless everything is perfect. That means cleaning everything very often, or having 5 heat sinks and 20 crucibles, and cleaning that mass of crap every few days.
3. Portability. Not even close. MV1 is a desktop unit. My Cloud Evo blows it away if I want to be at home and use a vape. The FW5 with an extra battery and extra tray or two is good all night and all fits comfortably in one pocket.
4. Cost. Buy two FW5's for the cost of one MV1 package, basically. Paying for MV1 batteries and fast charger is total rip off. FW5 crushes MV1 on that point.
5. Clouds. MV1 does not make bigger clouds. Both are about the same. Neither is a Cloud Evo, but you can get close.
6. Vapor quality. Neither is as good as say a Firefly 2, but the difference in taste or clouds is subjective preference, and not objectively different. The MV1 might have cooler vapor, but the FW5 has cool vapor even on high and the difference is marginal.
7. Looks. The MV1 is terrible looking. My wife hated it. Both the look and the sound it makes, eeeeeeeeeeeeehhh.... totally lacks sex appeal. I mean the FW5 is not as cool looking as a Pax 2, but the natural wood look never goes out of style and it's at least silent....
All and all, I like both vapes.
But I returned my MV1 for a refund and bought two FW5's and in no way regret that decision.