Quote from roadbiker : What is the difference exactly with this one?

+12 new playable characters.
Marvel: Doctor Strange, Ghost Rider, Hawkeye, Iron Fist, Nova, Rocket Raccoon
Capcom: Firebrand (Ghost 'n Goblins), Frank West (Dead Rising), Nemesis T-Type (Resident Evil), Phoenix Wright (Ace Attorney), Strider Hiryu, Vergil (Devil May Cry)

You can see the new character select screen here.
http://www.eventhubs.com/images/2...-capcom-3/

+New alternate costumes

+Two new maps: City That Never Sleeps and Days of Future Past

+Spectator mode (six at a time)

+Galactus (MvC3 Boss) is now playable offline.

+New game mode, Heroes and Heralds, team-based mode where you earn new abilities using upgrade cards, customize characters with new powers. Choose between Heroes defending Earth or as one of Galactus' Heralds. The "ability cards", which feature various characters from the Marvel and Capcom universes, unlock special power-ups, such as invisibility, super armor, and projectile invincibility, for use during mode-specific combat. Up to three different cards may be equipped at once, with more than 100 cards available to collect.

+X-Factor in the air, shorter duration, attack and speed boosts adjusted.

+Jill Valentine and Shuma-Gorath remain available for download.