If Haye is expected to at least compete at world level then this question should not even be a close discussion. Lets put it this way if Chisora fought either of the Klitchkos he wouldnt make it out of the first round.
at step up from Sam Sexton, and one that Del Boy still needs to make. Harrison got lucky cause the Champ vacated to fight Vitali and he hit got a fluke KO in round 12 when well down on the cards.