I played the crap out of my Soul Caliber 2, but I got my for my Gamecube because Link is a pimp! PS2 has Hieachi (spelling?) from Tekken and the Xbox version had Spawn... I wanted Link, so that is the one I got.
I just went back to EB today and picked up Republic Commando. After a few hours of playing it tonight I am going on the record and saying this game kicks some ass. If you like Halo or Halo 2, you'll have no problem with this game. It is even neater in some aspects because you control party members too — doing things like computer overrides, breaching doors, etc. And the interface is VERY easy. A+ in my book.