Jackson is a harder and better puncher than McCllellan IMO. He K.O'd much better opposition, and when Mike fought him at 154 he was better than G-Man ever was IMO. An absolute destroyer.
I don't count that stoppage over McClellan. G-Man was hardly fazed by some shots in the later rounds, when his condition really picked up. Benn didn't have to be a real hard puncher that night, anything probably hurt like hell. Nigel wasn't soft, either. I imagine him like Dick Tiger at 168; decieving KO record, as he could still crack, even if the KO ratio doesn't show it. I'm not denying he was a harder puncher at 160 though.