Mayweather in a very close fight. This isn't to say Mosley has no chance. I like these guys a lot at 135 in head to head terms. I think they join Ike Williams in that despite not having the "greatness" at 135 as some others have at the weight Leonard, Whitaker, Gans and Duran. They are cappabel of beating anyone at 135. Like I said I think it will be close, if I was betting on this I'd put some money on the draw. Despite the fact that Mosley has the better resume, he has always had trubble with guys who can keep their distance from him. Mayweather can keep his distance. Mu guess is Mayweather 7-5.
Mosley would win because at that weight, Floyd was a more offensive fighter letting his hands go. Everyone knows that the more you throw the more openings you leave and with Shane's speed and power at that weight, he could hurt Floyd. Also anyone that has seen Shane at the weight knows he was lightning fast and I think that alone would give any version of Floyd (especially an offensive minded Floyd) major problems.
Floyd is smart now. Corrales could have ended that fight with a good shot also, but Floyd played that fight smart