Both had crazy reflexes and were both arguably the best of their era. For me Roy was the more genetic freak but Floyd had a slightly better ring IQ and defense.
Both are multiple title champions and legitimate ones at that The only threat I could see to Floyd would be a young Camacho at 130 his limitless speed combined with his left handed style might be too much for Floyd i'm going with RJ
A better questions would be, who cares? You have two men, who potentially had the talent to be the GOAT, but never attempted to realize that ambition. It doesn't matter which of them had the greater athletic ability, because both ultimately trickled their potential down the drain!
what could Roy have possibly done to fulfill his potential? Winning multiple title while defending them in dominant fashion doesnt seem to be wasting his talent
I guess you can call RJ more athletically gifted, but that's where it ends. Skillwise, technical wise, Ring IQ, defense, timing, Floyd beats him out in every category