I don't believe Vitor is the better Kick Boxer, he has more power and is known for his fast hands but he doesn't have great movement and i can't remember him utilising kicks and knees too often.
If Vitor lands something big early he can end this fight fast, i just think Bisping has has been here before against similar fighters (not exactly the same, granted) and has had an appropriate gameplan.
People have been complimentary of Bisping's wrestling over recent years but the fact is he loses to wrestlers (Sonnen, Henderson, Rashad.. Hammill took him to the wire) and tends to do well against guys who he can get down.
I think he will get Vitor down multiple times during this fight and if he is going to win this fight he will have to.
I predict Diego Sanchez by Split Decision.