Bradley easily IMO. While he's not the biggest puncher, he still has a lot of power, especially with the volume of punches that he throws. He's also smart and is able to adjust. I think while Khan wouldn't get hit with SOME of the punches that Peterson absorbed, it would only take a few to put him in the danger zone. Bradley wins by mid-fight KO, if he could manage to survive then I think Khan would lose a decision. That being said though, the larger the ring, the better Khan's chances.