I own them both. They're the best mods I own and they each serve different purposes in my life. The iStick 50 I rock with a Subtank nano at work and out&about. The battery lasts forever. I chain Vape and it lasts me 4 days usually running between 17 and 22 watts. It delivers power and it's reliable. The mvp3 I use at home with a Subtank mini, between 23 and 27 watts mainly. I like them almost equally but I personally give the edge to the mvp3. I think the quality is better. Cleaner watts, built better, more quality vape. But that's just my opinion. Again it's close.