I'm a big fan of Lewis but let's be realistic, he was "one & done" against Rahman. Wladimir has always gotten back up.
For boxing ability i would say Vitali (and by a small distance) everything else favors Wald in my opinion,
A fight between Lewis & Wladimir at their peaks would've been a close one IMO. Both had/have skill, size, speed & power. The problem is Wlad's prime is now & Lewis had his long ago.
What kind of question is that? They both actively hurt the sport of boxing by having styles that are unpleasant to watch and by not fighting each other.