Holmes arguably won every fight in his prime (especially the 2nd Spinks fight). Lewis got knocked out twice.
Well he did get two highly controversial decisions vs Witherspoon, Williams, aswell. Although to be fair Holmes was 35 vs Williams. And I did think Holmes did enough vs Witherspoon, but still you do raise a good point. Holmes had his McCall, Rahman, moment vs Snipes where he could of been stopped. But Holmes managed to pull it out of the fire, for some people moments like in their respected careers. Could give the edge to Holmes when rating them, overall though as I said theres a good case for both men.
I think Lewis has more glossy names on his record, but perhaps younger fans don't remember that guys like Witherspoon, Cooney, Shavers, Berbick, Williams, Weaver, Snipes and even Frazier Jnr were really decent fighters. Certainly equivalent to Lewis victims Tua, Morrison, Ruddock and Mason IMO and better than Grant, Jackson, Golota and Briggs. They also have a shared victory over Mercer, another tough dude. You could argue that Holmes' wins over Norton and Ali were equivalent to Holyfield and Tyson for Lewis. With the Tyson and Ali fights equivalent as both were so badly faded. I feel if Holmes had retired at 50-0 or Lewis had beaten Bowe then that would gives each the edge. As it is I put Larry a bit ahead simply because he never got KO'd in his prime as Lennox did. However both awesome fighters!
Holmes has a significant edge in depth, but Lewis has better wins. You can argue it either way, depending on what you like.