I personally think Jackson he's the hardest p4p hitter ever IMO the guys hands were stone decent chin and good boxing skills
Very close fight, hard to pick, i would just give a very slight edge to GGG, by slight i am talking 51/50 and only because jackson is 56 years old.
That's for the boxers that give it a 101% effort probably. granite chin + big power vs feeble chin + huge power... I guess the first option wins 9 out of 10 times.