Dempsey was an incredible finisher. His 23 second dispatch of Fred Fulton might well be the single best finish in heavyweight history. Shame it wasnt filmed.
I think this partley reflects their difering philosophies. Tyson went for the kill from the opening bell while Louis liked to soften them up a bit before going for the kill.
These are the top two finishers in history in my opinion, but Tyson was better at finishing off a hurt oppontant. Faster, hit harder, threw more when he had his oppontants hurt. Louis was more accurate but I'd give the close edge to Tyson.