Tough choice, I like all 3. The garbage going on about MSHvsSF is crazy, but yeah I can agree with some of it, still, each VS game just brought something new to the table. I feel that CotA was crazy in the sense of juggling, such a unique system, although it all seemed like the seeds of things to come CotA still has some awesome things about it. Same goes for MSH, another great game, a bit crazy but fun nonetheless.
I guess I'll just go with XMvsSF 'cause it was mind blowing the first time I played it, everything about it just made me go nuts back then, I was hooked.
I love MSHvsSF on Saturn, specifically Survival mode, so much fun, unlocking the secret characters makes it more enticing.
Actually XMvsSF on Saturn was also cool 'cause of the extras as well.
Part of me wishes MVC had a Saturn release but the DC port isn't bad either, crossover mode is so much fun. Wish I could get to play that game more often. I dunno why crossover mode wasn't available online, a true lost opportunity there.