He was a pugilist specialist ! Rarely do you see his kind of technique and polish in a guy that size. He got careless on two occasions. I don't put too much stock on that as he avenged both losses decisively. (Joe Louis lost to Schmelling, folks didn't dwell on it). He's 3 or 4 alltime on my list.
He was very tactical, which led him to perhaps be a bit overly cuatious on occassion. But all in all, a brilliant package of size, power and skill. By quite some distance the best HW in the 90's IMO.
I think Lewis's chin is underrated. His power and strength were incredible. In every other regard he's overrated.