Actually, FFXIII is better on the PS3. But yes, generally, PS3 cross platform games are worse. I believe the PS3 version of SSFIV has 2 frame input lag...
Yeah, that's the one obvious exception, but that was never cross platform from the start. It's clear they just shat that out. There's no indication treyarch didn't put their all into the ps3 version. They absolutely would not have made it basically SD only (by european standards) if they could have avoided it.