from people that have all 3 versions, I have heard the PSP version *almost shocking* is the most graphicly advanced of the 3.
It's also portable, so you can play it anywhere you want
If you want a console experience (if u have a PSP 2000 or anything newer, you can plug it in the TV to play, so basically there's your PS2 game) I would go with the Wii version maybe.. that's if I were looking for a CONSOLE experience. If I was looking for anything, I would go PSP version.