Zero makes his second (or third if you technically count SNK vs. Capcom Chaos) versus game appearance in MvC3 and if his TvC iteration is any indication, expect pretty much the same for the most part from that game. We'll see though if Capcom nerfs his combo abilities that he had in Tatsunoko vs. Capcom because he was in the high in the tiers just because of that when you're in close to your opponent.
On the Marvel side, She Hulk makes her fighting game debut here and don't just ignore her assuming she will be a Hulk clone with his moveset. Turns out, she has her own moveset of sheninegans reminiscent of Rogue from the versus games and El Fuerte from the Street Fighter IV series. I would add a Run, Stop, Fierce joke with that, but I couldn't think of one right now with She Hulk. It would be crazy though if she has Fuerte-like mixups along with her grappling abilities, so she is truly an unique character to have in the game.
That's not all though since Gamestop also announced a Collector's Edition for the game which is 70 bucks. The important deal out of it besides the typical CE junk is a code for two DLC characters, which are Jill and Shuma-Gorath. Capcom has not officially said anything yet about how those two will be in it, but it seems like the plan on other part. Plus, it is only a matter of time when Capcom has to put extra fighters in as DLC in their games as it can be a good or bad thing to spin among fans and fighting game enthusiasts.
Capcom will continue to unleash more announcements in the coming weeks, so more with Marvel vs. Capcom 3 soon.