I don't know if you're looking to play Phantom Brave or to buy it as a "collector's item" or whatnot, but you should know that the PS2, PSP, and Wii versions are all just different variations of the same game. Seems like I run into the PS2 version quite often, though the Wii port isn't too rare yet.
Oddly enough, the Wii game contains a bonus CD-ROM of game artwork (I think?). Don't think I've ever seen that.
Eh, I'm not particularly jumping at the chance to get either. I say 'rare' because it's artificially so, usually. Price inflates, everyone scrambles for them, but not many care to sell. They'll probably become "Final Fantasy 7" rare. That being said both print runs aren't exactly huge, but would be workable if published by another company, as someone here said.
Baroque also has a PS2 version, and Baroque itself is a 'remake' of the Sega Saturn game.
I haven't played either Wii version, but I've played them both on PS2. I'd recommend both games even if just for play.
EDIT: Btw, if anyone's interested http://www.youtube.com/watch?v=R2iO5NzE_ik
this is the saturn version. In many ways I prefer this version of the game. First Person realtime dungeon crawling action, tons of incredibly bizaar enemies and way more scare factor. Where the PS2-Wii version I feel is much more cinematic and better handles the death and rebirth scenes.