The new issue of EGM (SC2 covers) has reviews for every version. The concensus appears to be that the XBox version is the way to go, followed by GC then PS2. The reviews ran through the usual stuff: really nice graphics, great combat system, great fun with two players. The few derogatory comments were limited to moderate-to-low replay value on the single player game and a Weapons Master (Quest) mode that isn't quite as good as other games (like Virtua Fighter 4).
Also, they mentioned that a lot of the new or unlockable characters are just existing characters with different looks. Still, this one is high on my want list. The first Soul Calibur is my favorite fighter EVER.