im gonna say floyd points but purely because mayweather has the mental game over any version of shane and thats what counts "can one adapt to ones situation"
I'm not sure if alot of people that voted actually saw Mosley in his prime at 135lbs, but he was a ****ing beast.
Floyd on points. He's the better boxer, period. Also, at this point Floyd seems to have grown into a full Welterweight body, so he might enjoy something of a size advantage on top of everything else.
A prime Mosley would follow up on that moment he hurt him, not gas without being made cautious by anything his opponent did.