Indeed the frequent change of hardware is frustrating... However, in regards to phones the 'changes' aren't too great. Personally I use my phone to phone people and text, sometimes play a game, sometimes check my email.. I don't need a video-calling, sky-watching, megapixel phone.. That, generally, does not work as well as the simpler model. From personal experience with this phone it is tricky to use, and so I am not particularly drawn to it. The V3 was attractive, however, this model is not slim and attractive, merely larger and more difficult to use for the Nokia/Sony convert.
I'm happy with my K750i.. As for brands? Sony or Nokia are the way to go for sure... That's just my opinion though.