I have played for about a year or so offline at MSU's video game club. I had a lot of success and was doing well with execution heavy characters.
My team is C.Viper/Nemmy/Strider
Nemesis stuff is about the same online, but I'm dropping a lot of my mid level and high level combos with C.Viper and Strider. Anyone else who plays these characters online know how to land their harder combos?
I having to double tap every input on Viper's box dash loops to land it and use EX seismo to make up for dropped timings. I do some stuff with BK cancels and BK cancel resets but NEVER can do this online. the 1 frame TK cancel into combo is somewhat iffy online so I don't bother with it.
Offline I do a lot of aggressive tri jumping and cross ups with Vajra assist, but online its so slow that I don't really get much out of it.
Strider's combos....make me cry.
Also, Just checked SRKs forum posts on UMVC3 online input delay....they didn't have a lot of nice things to say about it.
Personally from the viewpoint of having played this with really good people at the MSU video game club for a year, its hard to imagine people who only play this online. They are experiencing a completely different game.