Majority of jp players have ps3's, because 360 is kind of a failure there. Majority of good players here are on ps3, and it's usually the console used at majors. There's just too many scrubs on xboxlive (plus subscription fee) because of the type of player base the console has in general. You can probably find some good players here or there, but for something like blazblue especially, majority of the good players will be on psn, though I'm sure both have plenty of scrubs to go around. I actually think there are probably a lot of good players in the fighting game communities, especially like cali, that just mooch off their friends ps3's :V
Also, in Japan, they have just as many scrubs as we do, the environment just allows for cultivation of higher quality players is all.
Sometimes, it's like this.