From the footage i've seen of marciano, there is no doubt that he had a tremendous talent. For the type of fighter he was, a slugger, he was....in his time, the best in the business. I still think he would have been hard up against it to beat a true boxer like ali or frazier.
Expect things to be the same as the Williams fight. Lewis showed what he could do when he was focused against Rahman by pummeling him for 5 rounds before the knockout. Considering that was about 3 years+ ago and considering what vitali did to lewis, and considering rahman's record these past couple of years...i would predict an early knockout for vitali.
Its a shame about the heavyweight division at the moment. Vitali will rule until he retires over the next 6+ years. There is no one out there who has the talent to beat him...i saw mesi fight once and all i could think when the commentators said people were calling him the new rocky marciano.....whether it be on looks etc i don't know....was that rocky marciano was never a crap fighter as far as i know!