Mayweather would handily outbox Shane at this stage. Cotto, on the other hand, would beat Floyd in my opinion, by close decision.
PBF is in the same Position that DLH was in in the late nineties when the top three Welters were himself, Trindad, and Quartey. Oscar fought and beat them IMO, but Floyd has about four very good welters that he must fight and beat in order to be considered the very best but he hasn't done that in IMO.