I’ve been involved in this conversation personally with guys that know boxing better than basically anybody in the world. In two separate dinner conversations where this question came up I have heard all of the following side with Ali:

Bob Arum
Max Kellerman
Joe Tessitore
Mark Kriegel
Freddie Roach (who actually trained Tyson at one time)
Jimmy Lennon Jr.
Andre Ward
Timmothy Bradley
Tyson Fury
Kristina Poncher

And a few others that aren’t as respected as those listed above.

The only caveat being that a couple of them above said that maybe Tyson lands the lucky punch in 1 out of 10 fights. But outside that, the overwhelming majority think Ali wins.