If Kessler has a solid chin, then he'd take Benn apart and probably stop him. But I dont know much about his chin tbh.
I might go with Benn, simply because I don't know as much about Kessler. He's never been in a really tough fight, the way Benn was... over and over again. Kessler might come through a war with Benn with flying colors, but we've never seen him in such a war.
I understand your point, Zac, but Benn never fought anybody as good as Kessler @ 168, whereas I think Mikkel already has. Nigel wasn't that good @ supermiddle, IMO.