Marciano was the best HW of his era, fought the best fighters available during that time, and finished his career with a perfect 49-0, what more can you really ask of a HW champion?

It's possible Marciano gets beat by Ali, Holmes, Foreman or the bigger Heavyweights of the more modern era, but who cares, he did his thing.

BTW Joey, I think Pacquiao knocks Marciano out in about 3 rounds.