Povetkin takes this, he was a superior boxer. Bugner in another era would have been barely talked about. The seventies are considered the golden era for heavyweight boxing and therefore even the not-so-great boxers receive greater appreciation than they actually deserve. Povetkin on the other hand is a victim of the era he competed in. His best years coincided with the Wladimir era (2006-2014) which have a reputation for being the weakest in history. Povetkin was also a top contender in the era that followed, but we need to wait for the current era to complete for a better assessment.
Povetkin for me. He was good at closing the gap and imposing his bruising close quarters style on opponents