I started with the iPV D2. I can't complain, it's a very well built compact mod, but once I started playing with RDA's, the single battery wasn't cutting it once I turned the watts up. I still use it with my tanks because it fits in a pocket so easily, and the battery lasts quite a while at lower watts. About a week ago I got my X Cube II. All I can say is it that is amazing for the price point (a hair under $70 shipped from Wake and Vape). My favorite feature is being able to setup custom wattages. One of the settings I built for example is that it starts at 120 watts for a second to ramp it up, the next couple seconds it backs down to 90, then 75 after that. I did the update the day I got it, and now I have 180 watts of giddyup if I want it. I haven't played with temp control on either, so I can't comment or compare.