I seriously keep going forth between Black 2/White 2 and X/Y, but if you held a gun to my head and made me choose i'd pick the former. BW2 had plenty of stuff to do, and felt like more of a story, as well as there being some solid characterization throughout. I also have quite a bit of fun with the big battles in BW2, especially on Challenge Mode. And the battle themes are just so good (Ghetsis' and Iris' themes for two, are fricken amazing). I found the adventure to be very lively, so with everything said and done I have to go with BW2.