The reason, for me at least, that i like mvc3 is because i always knew another street fighter would show up.
It was more of a pleasant surprise on how it showed up though. Great art, a true sequel to the likes of sf2/turbo/champ/etc.
The reason however, that i love mvc3 more is because that everyone who played the 1st and 2nd has been waiting for the day the 3rd would come out, but many, like myself, thought that day would never come since the licensing was such an issue and until sf4 blew the scene back up and capcom realized that there was still tons of cash to be made in a 2d fighter, they didnt listen to the community for mvc3.
Plus i feel like ive been waiting for mvc3 for a decade or more.