Most would probobly say hagler,but then again he was sort of an accumulation type of puncher,but Leonard had some pretty nastly kos even in the upper weights where Hagler never ventured. Hearns had more power than both.
leonard had more "snap" at times and some solid knockouts but hagler was an all time great hitter when he sat on his punches
Hagler had more power through being naturally bigger, p4p I might give it to Leonard.... maybe :think
Leonard scored a few more impressive looking KO's, but that was likely due to his superior speed and combination punching more so than pure power. Both were very good, solid hitters but nothing devastating a la Hearns. I do think Leonard was a bit more capable of ending or changing a fight in an instant than Marv.
Both often underestimated punchers. leonard was vicious with his punches at 147 and seemed to carry his power well up in weight too.
Hagler had more pure power. He was definitely the more heavy handed fighter, but Leonard was the sharper puncher.
Leonard has exactly ONE fight "where Hagler never ventured." Donny Lalonde. And he forced this LHW to weight drain to 168 to artificially have two weight-class titles on the line. Leonard was the more skillful boxer. Hagler was clearly the harder hitter.
Hagler definitely. Marvin was naturally bigger and almost always got his foe out sooner or later. Leonard's power was more velocity-based.
Leonard seems to have the more dramatic power, apart from vs Hearns Hagler tended to grind opponents down. Leonard threw punches out of nowhere and his KO of Hearns shows his explosive one punch power. he had a few fights where he turned it around with a sudden blow.
Leonard had snappy, the-punch-you-don't-see-takes-you-out kind of power, Hagler was the heavier hitter imo. I also think Hagler had the nore long-term damaging kind of power too, many men were not the same after fighting Marvin. Often overlooked with Marvin is that he also had that "cutting" power, he was a slashing puncher; look at Minter, Vito, Hamsho and Sibson. Minter & Vito were bleeders before they fought Marvin, not sure about Hamsho, but Sibbo was not known as a bleeder until, and after, he fought Hagler.