Ali had less loses vs top flight comp but some of his fights were close and debatable on the other hand Charles was on the wrong end of some decisions- in particular his fight with Harold Johnson which i think he deserved- and a contro loss to Elmer Ray Charles defeated fighers who were greater in a p4p sense
Archie Moore for example in a p4p sense is easily greater the Liston, Foreman, Frazier etc but Ali's comp was awesome, best of any heavyweight
Ali's record is amazing, with victories over Moore, Liston, Patterson, Williams, Folley, Terrell, Frazier, Foster, Norton, Foreman, Lyle, Shavers, and many other top light heavyweights and heavyweights. He never lost in his prime. Between 1960 and 1977, he only lost twice, to two of the best heavyweights at the time, and he avenged both of these defeats twice over. He took on all comers and he was never knocked out. I like Charles a lot, but Ali's record is better.
The thing is with Ali, a lot of his opponents have been overrated just because they fought him. Zora Folley, for instance, or Oscar Bonavena - solid fighters, but no more special than Del Flanagan or Shorty Hogue and probably not as good as Sandro Mazzinghi or Virgil Atkins. But somehow we feel obliged to mention them on Ali's resume as though they hold a massive amount of water as top flight opponents. They were good, but not really good. You thought Jerry Quarry and Ron Lyle were really good? Watch Enrique Bolanos or George Araujo and you'll see that they're easily as good, yet you wouldn't necessarily hold them in as high esteem.
Pound for pound I would have to say that Ezzard has the greater victory to win every fight in a trilogy against Moore is greater then 2.1 against Frazier and Norton plus he beat almost everyone on the black murders row. Also Charles is normally regarded as the greatest Light heavyweight of all time despite never winning the title, which shows the calibre of his win. Only Greb has better wins maybe Langford but nobody else.
How many fighters have been regarded as the best ever in their class without wining a title? Some lone voices argued that Peter Jackson and Sam Langford were close to their peaks. Mr Charles seems to be something special in this regard.
p4p Charles, heavyweights don't even come close a bit. Ali gets treated so good on most p4p lists because he's the greatest hw ever and the hw champ is h2h the strongest man on Earth, but I don't really care about that and Charles was p4p just the better dude. Charles got Charley Burley on his resume, the same Charley that knocked Archie Moore down 4 times in 10 rounds and might have KO'd the man had it been 12 or even 15 rounds (Moore was shaky at the end) He also got the lhw monster Archie Moore on his resume. Jersey Joe Walcott Joe Louis (Louis wasn't prime, but Charles was the smaller man) blablabla Better wins than Liston, Foreman, Frazier imo.