Does it really matter since they are both long dead, never faced the same opposition and their careers never came close to crossing.
It's hard to pick against a guy who killed an opponent in the ring and had another die shortly thereafter. I take Baer.
From what I've read when Baer was on his game his single punch power was exceptional. He was one strong dude.
Baer was a tough, strong guy but seriously, press the eject button and put Cinderella Man back in it's case, he was nothing like that film depicted him to be. Rocky had the bigger punch.
Marciano. I'm not 100% on this, but I think Louis (common oponent between Baer and Marciano) said Marciano was the hardest puncher he faced.
I know Jethro, after a plate of grannys grits, would wrestle an then Knock out a gator with the right like his paw taught him
As for louis saying that rock hit the hardest, I believe baer broke his hand early in the fight and without that equalizer he got steamrolled. Chances are Baer didnt get to show Joe his true power.
Hardly the same man when they fought this common opponent. Baer and Louis fought in 35 while Rock and Louis fought in 51 for Joe's last fight before retiring.