Shockingly, I'm gonna go with Floyd, although it is tight. I just feel that the 3 most impressive wins Oscar has on that list (JCC, Pernell & Quartey) were all well past their best, and I thought he lost 2 of those (although this evens up with the Trinidad fight & the 2nd Mosley fight).

I'm also taking the manner of performance & how far out of their comfort zone they were. IMO Mayweather isn't and never has been a 147 fighter, whereas ODLH was a natural welter who was great at getting down early in his career, and eventually grew into a natural LMW.

Floyd on the other hand was a natural 130lb fighter, who grew into being a natural 140lber and climbed higher to go after De La Hoya. I was also more impressed by the manner of his victories, and in truth the only guy he ever had any difficulty with was Castillo, and he had him figured out in their rematch. One thing that irritated me with Oscar was that he never gave rematches to guys who he got a lucky decision over, only where it suited him. Should have fought Trinidad at 154 though.