If you have an arcade stick they all play the same. The only differances are the special charicters and the Graphics. Here is my Breakdown
1.)PS2 Good but has slowdown occasionally and IMO Heihachi is a waste
2.)GCN Great. Much faster loading,better graphics, 480 P rog Scan,Link is a better charicter
3.)XBOX Great,Fast loading,best graphics,5.1 Digital Sound,480P and 720P,Spawn is a great charicter.
I say buy the Cube or Xbox versions. The thing that sucks about the Cube version is that if you want to use a stick you have to buy one since none of the controller adapters let you use digital sticks on the cube. Only Dual Shock2 Pads.