The innovation in this otherwise incredibly familiar port is touch control. Tap your opponent (front or rear panel) to slap, tap your gauge for a Hyper Combo or... no, that's it.
Trouble is, spamming the touchscreen is too easy - you don't learn the techniques to improve your game that way (try the excellent Street Fighter IV iPhone app to see how it can be done). On the upside, you can block touch players in online fights.
Stick to buttons - Vita's D-pad does a solid job - and this is authentic stuff. The rocket-speed three-on-three action is gorgeous, with big, bold character sprites.
Online works great so long as you're near the Wi-Fi router (or else it gets choppy) and it boasts uploadable replays. You can even share DLC with your PS3 copy - here, violence is golden.
An impressive port that will satisfy seasoned fighters, though it concedes to newbies in the worst way possible.