PS4, mostly for the exclusives, the fact that I have a good PC for gaming already, and the fact that I already have an PSN+ account so, you know, PSN games and free shit.
This entirely is my position. I also have a Vita so I get even more from the Sony platform.
God, I want a Vita so bad. I had a pre-owned PSP a while back that I used to play all my virtual PSone games, and it was goddamn glorious. But it was a piece of junk. The battery wouldn't stay connected, and it would randomly shut off (and not save), but it did it so randomly that it was never enough to trade it in, or do something about it, you know? Like, it would do it twice in a day, and I'd be really pissed, and then it wouldn't happen again for 2 months. And then after those 2 months, it would happen again, and then again the next day, and maybe even a third time an hour later. And then it wouldn't happen again for another 2 months.
Eventually, I got mad and broke it, lol.
Seriously want a Vita, though.