In terms of boxing ability? I would say Lopez. Watched a break down of his techniques not too long ago, the guy was a boxing genius and had an answer for almost every situation.
Greater is tough. Lopez's longevity and dominance counts for something but he didn't risk it when he should have (Carbajal/Gonzalez). A win over either of them around 1994 time would have elevated his standing that much more. Don Curry deserves huge credit for becoming undisputed welterweight champ. With hindsight, beating Milton McCrory to do it doesn't seem an amazing feat but that KO was as good as it gets. A short prime but he was p4p no. 2 at one point. Was Lopez ever quite that high? Better - I think that goes to Lopez. He was technically superb. Curry was too, but maybe had a few more chinks in his armour that were exposed later on.
Curry had overall more chinks - for instance he often pulled straight back from punches with his chin in the air - but he was a much better infighter than Lopez, I'll give him that much.
Lopez was greater. Longevity and he proved more.. Donald just had a tough fight which might have turned thing badly
Curry had it all but was so insistent on leaning back as his main defensive go to. The guy has amazing hand to eye coordination but won’t parry. So frustrating to watch. Plus he got koed a few times and still wouldn’t change his defense.
Ricardo Lopez and I don't think it's close. The guy was a master and in my opinion had no weaknesses.
It's a matter of how you view a short prime with some good names on the resume, and also being considered as the best fighter for a spell VS being undefeated, consistent, many title defenses, but with a less stellar resume. Hard to say honestly. I would say that Finito was greater just due to the fact that he kept everything together in the long run, had the intangibles, remained unbeaten, and didn’t fold even when met with adversity (Rosendo Alvarez). But it would have helped if he had his share of facing other talented fighters within his weight class like Too Sharp, Arbachakov, Carbajal. Curry at least fought a defensive genius in Starling and a fast, slick Ali-type like LaRocca. Curry had hit a much higher plateau than Lopez, although Lopez remained great much longer. Skill wise I think they’re both close as well. Curry showed much better infighting while Lopez had much better footwork. Curry was more physically talented of the two but Lopez was more crafty. At their best they both looked close to flawless in terms of technique, although Curry’s defense became much more porous and open later on in his career. Lopez’s skills never seemed to have deteriorated.
Lopez is a boxing master, but he does lack an inside game and showed some weakness against Rosendo Alvarez when they fought both times. He was very fortunate to receive a draw in their first fight, which I thought Alvarez deserved to win. Every fighter has a weakness, no fighter is ever “perfect”.