Exactly. Comparing someone who has incredible punching technique to a slapper...you can't be serious. :-(
Without giving it a second thought, Juan Manuel Marquez by a considerable distance. Success through more weight divisions, better resume, superior fighter H2H at his best IMO. Make them the same size and I'd take Marquez all-day with his skillful pin-point counterpunching, versatility, and superior timing.
Calzaghe. He beat an old Jones and Hopkins and Marquez beat an old Pacman. But Marquez lost easily to Mayweather and lost to John. This is not the wipeout the polls say.
I don't think it works like that for an unbiased fan. Which is why you don't see more serious scholars of the sport rating Rahman above Tyson and saying his one-punch knockout of Lennox>Tyson's whole career. That's simple talk. Anyway, Marquez by some distance, for me.