I was thinking about this, and I am curious to see what people think.

In the 80's
I think he would beat Hearns, but I think Leonard would beat him decisively, I also think Duran would be too good on the inside for him. Benitez, I am not sure, he was so good defensively, but he didn't take fights seriously, and I think if he didn't train well for this fight he would lose it, but if he trained hard he would likely win.

In the 90's
I think Oscar De La Hoya would for sure beat Margarito, too good of a boxer, and was big and strong enough to match up physically against Margarito, I don't think Mosley would have beaten Margarito, his style just doesn't work moving backwards, and Margarito would throw, and land more than him. I think Quartey would stand a good chance of beating Margarito for the same reasons as Oscar, but a different style, I think his jab would pick Margarito apart, and he is strong enough to hang with Tony. I think Margarito beats Campas, I also think if he can handle Tito's punch, that he would wear Tito out and ko him.