In my opinion is impossible to come to a conclusion other than both Margarito and Cotto would be competitive against the top welters of today. Success in the sport of boxing at the highest level is mostly tied to the conditioning of the fighter. Conditioning happens at the training camp prior to the fight, so this leads me to agreeing with the good ol saying that you're only as good as your last fight. But, both Margarito and Cotto are good fighters to bet on though, depending on the stylistic matchup. I still think both at their prime would lose to Pac (and Floyd) even this version of Pac (38 years old) today.