I haven't watched a great deal of KC before and just watched his first fight with Canzoneri and was very impressed, he looked to be royally jobbed in the decision to me. Similarities, ofcourse in the basic stance/half guard, but many differences, Kid uses far more lateral movement using his jab to circle, while staying out of range, Floyd prefers to typically be much more stationary or move back in straight lines/diagonally, although occasionally he too circles. Kid leads with the jab, Mayweather uses his speed to lead with rights/hooks alongside lead jabs KC is willing to exchange and be in striking range far more often. He throws allot more, but also gets hit far more. You won't see Floyd look to exchange the same way as Kid does at times where he throws for the rafters square on. FMJ certainly has the better inside defense of the 2, getting his hands up. HE also has the better head movement/slipping ability While FMJ likes to effectively play the role of a fencer, look to land something sharp and move back out or look to set a trap, roll and counter. Floyd also half steps more with his footwork, which imo sets up his opponent better. The other thing is there are clearly 2 versions of Mayweather, the more aggressive boxer puncher at 130 who would look for combinations and to walk his man down and the sometimes more negative version above that. The Mosley, Gatti, Judah, Corley fights show the negative style isnt always the case