Both Ali and Louis fought some great competition. It’s hard to beat Ali’s resume though. He literally fought 4 top 10 HWs of all time (Liston, Frazier, Foreman, Holmes). He beat three of them. Holmes was at the end of his career so it wasn’t much of a contest. He also fought some other really solid opponents.

Louis proved to be able to completely clean out his division. He dominated the division for years which is tough. And again, he wasn’t fighting push overs. He fought some real tough guys.

Ali and Louis are solidly #1 and #2 HWs. Other people can change places, but they are set. I think that Ali was better.