Mayweather was awesome at 130lbs against Juuko. That might be his second best showing at the weight after Corrales. He was also good against Hernandez and Manfredy as well.
I heard Corrales actually weighed in over the 130lb limit (at 133?) and the fight went on anyway. His comp is clearly better at 130-135 but that doesn't mean he wasnt still at his best at 140. Also Gatti and Corley were top5 and top8 and 140lb belt holders when he faced them so they werent quite bums. Contary to popular belief Mayweather did try to make big fights at 140 too.
im not saying he didnt try to make fights and fight big names at 140 he beat decent guys but im saying he is not as good at 140 he was slower and less mobile at SFW he was quick and used alot of movement