I'm not going to argue the state of the PSVITA but I think it is safe to assume that the PS4 has surpassed the PSVITA already by a small margin as of now. They are probably equal when Vgchartz updates last week numbers and Vita is surpassed then with this week numbers.
PS4 is indeed a fast selling console and unfortunately the VITA as a standalone console is more or less dead in NA, on life support in EU and does reasonable in Japan. I enjoyed the games on that system, especially the indie games that I prefer to play on a handheld than my PC/smartphone. Nevertheless I don't think Sony will ever come with a new handheld again. They'll probably bring some sort of peripheral for xperia smartphones to play Android games.
But I'm curious about my favorite handheld game though. Gravity Rush. We now that there is a sequel in the works but I actually hope that this game will be available on PS4 with the beautiful cell shaded graphics and enhanced gameplay.
Stories unfolded with my home made rap songs. Feel free to listen here with lyrics: https://youtu.be/vyT9PbK5_T0