Floyd all day long. Pac has been stopped twice and both times he was basically knocked out and that was against tomato cans. Pac dont like it when he gets whacked. Now just because Floyd dont get hit too much doesnt mean his chin is inferior. And you never see him getting timid like Pac.
I think Floyd got a slightly better chin. I have seen pac's neck snapped back several times on chin shots, while floyd doesn't but then again, Floyd is slipperier to hit clean.