In terms of ability, where do you guys rank Ricardo Lopez ?

This comes under the same scrutiny as every other remark about Lopez. We just don't know how he'd have looked against elite level opposition. He never had to prove himself because he never fought anyone he had to prove himself against, at least until he faced Alvarez later in his career. We saw how much difficulty he had in those fights, and that was against the best fighter he'd ever faced and the first one to really out-muscle him and push the pace on him. Granted, he was past his prime by then, but he looked damn good in the rematch regardless. What if that had been Chang pushing the fight on him?

See above. He was obviously extremely well schooled under Nacho Beristain, but how would his extremely tight, textbook style fare under real fire? I personally believe Marquez has proven his abilities more thoroughly, even if Lopez was a bit tidier.