Well, the all time best is purely just a personal opinion whether a person is keeping it real or not. For me, I think PBF is arguably the best talent I have ever seen. But if he beat the winner of Pac/Cotto and then a Mosley then I would say he has a great argument for being the best of all time. If he defeated those two fighters then he would have been the clear best at 147, the weight class he needs to put his domination to. If Williams can make 147 without draining then beating him would be an exclamation point,and a better win than anyone, that even the most denying hater can not argue.