Roy Jones' defense was based solely on his reflexes. Mayweather's defense is amazing because it's based on technical skill (shoulder roll, parrying, etc) AND amazing reflexes and intuition. Hopkins has very good technical defense and is a master at angles. Mayweather is a defensive genius.
same with me. Quality of opposition also. Hopkins fought the best and Floyd did not. When and if Floyd fights a fast fighter like Shane or Pacman we might find out more about his defense and chin. We really do not know.