I'm definitely on the rx200 bandwagon. I love it because of the battery life, and the wide range of options of things you can do with it doesn't hurt even tho I'm not big on the temp control stuff (yet continue to get it to work with premade coils and usually regret it) and it fits the hand sooooooo well.
I have a fuchai too and it fits almost as well as the rx200, but with only 2 batteries, I found myself pacing to keep from dying at work. The TC on it brings the fail tho. Way too cold.
I have a snow wolf, and it's my house queen right now, I'm not terribly impressed with it. It is a nice functional box, does TC (better than the fuchai) and the fuchai seems to edge it out on battery life.
I'm currently looking into getting a couple of cuboids. They are smaller, seem to be well constructed, and I'm a fan of bigger screens. Plus cheap and all the wattage you could want 150. (But I've seen it said that with a firmware upgrade it'll do 200w.)