Are you kidding me? I'd expect to compare Floyd's defense to the likes of, Hopkins, James Toney, ect. But JMM? I know he was good when he was younger, but i don't think he'll be remembered as one of the greatest defensive boxers in Boxing history.
Floyd is better defensively because he maximizes his technical abilities with great athleticism, and his dimensions make it possible to make defense a great priority. Marquez may have competed in his physical prime, but he has to take far more risks to create an effective offense, and thus eschews his defensive capabilities, especially now that he's older.
Mayweather doesn't body punch? Mayweather rarely creates angles? Counter punching is defense? Really? atsch