I do question how much of a puncher Jeffries really was. He was apparently 6’2 220lb, yet he allowed 163-180lb men to last 20-25 rounds with him I mean how long do tiny sharkey fitzsimmons Choynski last with a prime foreman or Liston?
Equal in terms of heart, toughness, and ferocious fighting ability. Slight edge to jeffries in raw power and brute strength, might have better body shots and jab. Roughly equal in stamina. Marcianio is clearly superior in terms of ring generalship, resume, and quality of opposition. Neither of them had particularly amazing eras but marciano fought seasoned veterans of the sweet science while most of the guys jeff fought were barely above modern golden gloves champs in terms of skill.