I'm going to go with Sonny. George Foreman sparred a lot of rounds with Sonny and fought a classic with Lyle. He always said that sparring Liston was the most dangerous thing he ever did. That's good enough for me.
On the other hand him and Shavers named Ronnie as the hardest punchers they ever fought. Sonny might hit harder though, I'm sure there is a decent case to be made.
While I respect Lyle’s punching ability, Sonny Liston devastated an entire division with his own. I’m not even certain that Ron ever stopped a ranked opponent except for maybe Shavers and that’s if Shavers was even ranked. Not really a question for me.
He didn't stop any of the fighters who were ranked at the time of the fight or the same year (Bonavena, Bugner, LeDoux) bar Shavers, but you could add third round demolition of Larry Middleton who was very recently ranked in the top ten and had a strong losing performance against Quarry a fight prior. On the other hand Earnie named him the hardest puncher he ever faced, and so did Foreman (when hit with a hellacious left hook from Cooney, George said he knew he had to finish the fight quick, or else it could venture into the Lyle territory). Bugner said Lyle nearly killed him. What definitely set then apart was the fact that Sonny applied his power with much more accuracy and craft.
Id say about the same in terms of one punch power but I think Liston hit harder with shots that werent power punches, if that makes sense.
This might be a misleafing statistic if you consider that the contenders Lyle stacked up against were more durable than those that Liston stopped.
Were any of them more durable than Wayne Bethea whom Liston became the only man to ever stop ? How about Henry Clark ?
Liston had the more potent left hook, Lyle had the devastating right hand. I'd maybe just slightly prefer to take a Lyle right hand out of the 2 but either way I'd be out for the count of 1000