Grant is both underrated and overrated.

Grant was one of the most overhyped boxers of all time who ultimately failed to live up to expectations, he never seemed to recoup after his title loss to Lewis.

He also has lost only a handful of fights to either top contenders or hard punchers with circumstances in a long career with decent opposition.

The comparison with Wilder is valid for several reasons. Wilder is similarly hyped, Wilder has similar record to pre loss Grant, he is super tall and powerful like Grant and supremely athletic like Grant.

Some notable differences though, Grant is much bigger than Wilder. Grant is among the largest of boxers whilst Wilder is a top heavy, chicken legged, skinny gutted beanstalk. Grant has a big head and a solid chin, Wilder has a pin head and a weak jaw, he even got KO'd allegedly in sparring!!. Grant faced many good opponents in his career. Deontay faced SOME comparable opponents to Michael Grant (analysis of Wilder's record reveals that some of the journeymen opponents Wilder faced were of comparable level to Grant's journeymen). But overall definitely Grant faced much tougher opposition even before Lewis loss!! Grant could actually box some, Wilder is strictly a puncher. Grant had stamina, Wilder has no stamina.

Conclusion: Wilder will probably be exposed, I don't think he is or will be as good as Grant but that doesn't preclude him from ever winning a title as happenstance plays it's role too. Wilder would still KO anybody prior to the 80's, only possible exception being Foreman and that's a big maybe!