This for me. It depends on what punch specifically were talking here. I doubt Ortiz' best once shot body work is better than Cotto's.
I think Ortiz is one hell of an explosive puncher at Welterweight, hard to believe he was hitting 140 pounders about only a few fights ago.
Despite the myth that Cotto is a massive puncher, he never had one punch KO power, majority of his ko's were result of accumulation, Ortiz on the other hand has one punch, fight changing power
Cotto used to be the hardest body puncher in the game along with Margo but he felt those overhand rights from Shane and he surely felt those swinging punches from Pacquiao and uppercuts from Margo so it's difficult to say if he is the biggest puncher, specially when everybody relies on power to make an early impression and keep opponents under control nowadays, Canelo, Bradley, Khan, everybody. But in terms of strength, i don't think that at this point Cotto is stronger than that guy with that upper body that we saw in Ortiz at 147. Sure, Cotto is 154 and Mayweather 151, expect Miguel to grow overnight to 160 plus while Floyd will remain under 155... But Cotto cannot have Floyd leaning back against the ropes and taking sloppy punches like Ortiz delivered sometimes cause he doesn't have the mindset to finish Floyd right there and then... He knows he'll probably be uneffective and punch himself out... This is the greatest improvement of a pure body snatcher to a boxer-puncher who can move and jab and keep it up. It's not so important that he is or is not the hardest puncher rather than Ortiz cause they are not hitting a heavy bag but Cotto is surely much better and has better chances at this weight than Ortiz had at 147.
easily Ortiz. He has enough speed to create that explosiveness. Cotto(e) on the other hand isn't explosive at all.