3DS because of Monster Hunter and Pokemon; also throw in Zelda and Mario as well. Monster Hunter is hitting the 3DS before Vita comes out, so expect the 3DS to have a huge lead over the Vita.
Now as for the Vita: The problem with MGS Rising, FFX, MGSHD, UMvC3, etc is that they're also coming to the PS3, and I rather get those on PS3 than the Vita due to playing it on bigger screen + better online. Those games would have made the Vita more appealing if they weren't coming to the consoles. Though, it's good for those who haven't played the games yet.









