Not so sure I'm picking this up, but I wouldn't get the 360 version unless I had an arcade stick to be honest. Load times, install times and graphic comparisons aside, the 360 controller isn't really built with the D pad as a high priority.
Not even commenting on the quality, the biggest issue is the 360's D-pad location. D pads require stretching your thumb further cause they're not raises off the pad as high as sticks are, when you put them further away from your hand, it makes them uncomfortable. The 360 made the stick the high priority - making that extremely comfortable by putting that on the left assuming most games would use that to move, which is true... but it makes fighters unplayable to me on the 360.
Just my thoughts. If you're considering which version to buy, put your left thumb on your 360's control pad, try pushing that for a few minutes and ask yourself if that's comfortable.
For all I know the 360 version just goes ahead and uses the left stick to move instead... which makes quick, short sidescrolling movements more sluggish.
Of course you can always just get a Hori stick, which is something people online say a lot - I just don't actually know anyone who likes fighters enough to buy arcade sticks for them.