Hiya,
I haven't played much of Guilty Gear at all, and I hear things can get crazy, but...
It's Marvel vs. Capcom 2 for me.

Of course, it sucks when people only pick top tier characters and cheese, but when you've got some friends with variety, it's a LOT of fun.

Main drawback of that game was music... >_< That, and story (well YOU try making a story for 50+ characters!

They prolly did in Capcom vs. SNK 2, huh). BUT! Take Marvel vs. Capcom 1 music and story and stick it in with Capcom 2, and you've got yourself an AWESOME game. Remember in Capcom 1, when one of your characters died, the theme song of your remaining character played? I loved that so much!! The graphics also seemed a little flashier in Capcom 1...
Thing about KoF games and Capcom vs. SNK games is that they seem a little slow to me... not that I'm the best at them or anything, but the dashes and junk just aren't as nuts as Capcom 2...
~Kap(com 2)