It's pretty good.
The resolution is crisp, but seems to scale down (either sub native or AA turns off) when battles are hectic.
I've had one instance of slowdown, it was a sharp drop in the village area of the first level, where you come out to china blossom trees.
Overall, I'm quite impressed, especially when the camera pans in for finishing kills.
This is my first experience with NG2, outside of the 360 demo years ago. I'd always wanted to buy it - but held off until (when)I heard vita was having its own version.
The Vita was also my first experience with NG1, as well.
As a first time player of the series I like them both.