I've heard the Wii version has a bit more bugs when compared to the PS2, but that really doesnt matter, cuz I got the PS2 version before the Wii version even came out, and it would be a waste to get both versions.
more vibrant but in a game that is supposed to look like its rendered in water color it actually hurts the painted look of the original, though I would like to try the wii version on giant wide screen since thats the one new graphic feature