Assuming it's both at their very best (so let's say a 2006-07 Cotto and a 1984-85 Curry) then I'd definitely be picking Curry here. A short peak, sure, but during it he really did look like the complete fighter. Even at his best I always thought Cotto was a little lacking in the ring IQ department, a little too hittable and had a tendency to slow late on. I can see Curry taking the fight to him, landing lots of uppercuts through that guard of Cotto's (he never learned to deal with that for some reason) and generally just being too slick classy for him. No doubt who had the better career and that's Cotto by a street, but much as I like him Cotto never quite had the look of a truly, truly great fighter at any time. Curry did, albeit for a short while. Curry by late TKO.
Tough fight to figure. Curry better get a good lead early because Cotto could make it a war and win with Curry quitting like he did against Lloyd.
Donald Curry of 1985, was a very skilled Welterweight champion. He had good wins over the likes of Marlon Starling , Nino La Rocca, Colin Jones and that sensational knockout of Milton Mc Crory to unify the belts. Miguel Cotto had the two great fights with Antonio Margarito, and destroyed Sergio Martinez, to win the middleweight title. Cotto is a heavy hitter and would hurt Curry. Donald stays upright after many shaky moments to win a majority decision. After he was thrashed by Honeyghan in Sept 1986, Cotto would be the victor.
I'd pick Curry if we're talking about both fighters at their peak. Before the Honeyghan fight, Curry was a great fighter. Curry was nothing short of magnificent against Marlon Starling (second fight), Elio Diaz, Nino LaRocca, Colin Jones, Milton McCrory.
Miguel Cotto was a lot better than all of those guys. (Elio Diaz?). And both Curry and Starling fights were close. Was Donald Curry ever better than Shane Mosley? (Not in my book. And I watched them both coming up.) Cotto beat Mosley at welterweight. I'd lean toward Cotto. I don't think either gets stopped, though. Good matchup. But Curry isn't blowing Cotto out by any measure. Nobody did. (Can't say the same about Curry.)
I'd just like to add, Curry's boxing style was magnificently minimal. Text book mastery is to use minimal movement and waste less energy. Curry had that. Awesome fighter.