Need advice on getting a PSP or Vita?

[grim_tales]

Hey,
Although I've always been a Nintendo kinda guy, I was thinking about getting a PSP or Vita so I can play an awesome looking visual novel called Dangan Ronpa (Trigger Happy Havoc) and other Japanese games (I'm in a VN phase right now), but I dont know which PSP model to get (there are too many) or whether to be more future proof and get a Vita. Can you still download games on it like the Persona series or Corpse Party?
Games like Zero Escape and Phoenix Wright are awesome and Dagan Ronpa sounds right up my street
Should I get a 'latest model'PSP or a Vita? I dont want to spend too much money though.