GameTrailers has a number of Ultimate Marvel vs Capcom 3 clips today from the San Diego Comic Con build of the game. The quality is extremely nice on these, even though the gameplay can be really one-sided at times. A few of these clips show off some of the new properties given to returning characters. See if you can spot the differences in action.
Interestingly enough, Famitsu announced (via SiliconEra) that Capcom would be adding new gameplay modes to UMvC3 via DLC. The first is apparently an unlimited hyper combo mode. I suppose this means that you and your friends can do nothing but shoot lasers at eachother for hours if you so desire.
[tip from Alex M]