Damn, this is like asking me which is better, cheese with wine or Corona with lemon? Damn, if you held a gun to my head, I'd be inclined to say The Marvelous One. Chavez started out 89-0-1, but Hagler in my view, faced tougher opposition.
I know Hagler's career well, saw many of his fights and respect him highly. Don't know as much about Chavez. But his record is rolled gold. He was 87-0-0 til he drew with Purnell Whitaker, and hadn't been off his feet until 89-0-1 when he met Frankie Randall, who beat him on pts. Too hard to call this one!
I pick Hagler because he became a better fighter after his early losses in which he avenged and never definitively lost afterwards. Chavez, in most observers opinions including mine, was clearly beaten by Whitaker. Also Frankie Randall was an easy call.
Why is Chavez hands down higher than Hagler pound for pound? :huh Because he weight climbed while Hagler stayed put? I'm not casting aspersions on anyone in particular but there is a bad case of not understanding wtf p4p is about on here and it may explain the certitude that Chavez is "greater" regardless of who is h2h better.