Floyd supposedly hits very hard according to practically every fighter he's ever fought. There's a reason most good fighters hes fought come in with near career lows in throws and lands after he tags them a few times. Floyd is just very disciplined with how much he pulls his punches. Floyd has to be one of the most calculating fighters we'll ever see .. As much as it pains me to admit..Floyd is amazing when he goes on the offensive. When he's throwing punches he looks unstopable. He can go from pitter pat punches, to an offensive assault of hard punches then immediately start countering.
Marquez has power and when he's going forward throwing punches he can be lethal sitting down on them. He just fights so..weirdly agressive off the back foot with his counter punching and combinations that we forget he can come forward and throw bombs if he sets his feet. Thats what he did with Pac. He caught him the same way a few times then he unleashed it. Martinez did it to P Will too. Watch how they both set the punch up, land it a few times as what seems like a "Ok, I got this" then they just exploded.
I think Floyd has more power but is more cautious. Marquez will take a shot if he can land 3. Floyd can give 3-4 shots and take one in return if he chose, but he instead gives 1-2 and takes none.