Conor has KO'ed Aldo and Alvarez. He has also knocked down iron chinned Nate Diaz. Conor's power is no joke
But Hendo knocked Wanderlei, Bisping, Shogun, Fedor, Busta, Boetsch, Lombard, Feijao, Babalu unconscious. Most of those were not TKOs. They were extremely scary flatlining KOs. Dudes were completely out cold. Busta wasnt quite yet but he would have been had the ref not saved him.
Conor only throws straight punches (and occasional Overhand at the taller Diaz in their first fight). Conor is better at straights. Hendo loads up more, sure, but Conor could do the same but he just chooses not to. Conor likes to fight long so he only throws straights and rarely hooks. Hendo usually fights bigger and taller guys so his straights are not as effective. Hendo dropped Wanderlei with a left hook and then dropped the fatality blow. Hendo's VERY SHORT punch to Fedor caught him flush on the jaw and Fedor never saw it coming from behind.
Gotta go with Hendo here. Conor is an amazing striker but once Dan touches your jaw it is usually lights out