Purely in terms of ability, I don't think he's any worse than a Jose Luis Castillo. He'd be a pretty dominant lightweight if he were around today.
Better than good or even a good champ, I would qualify him as an excellent champ though not an ATG. One of the rare Mexican champs with an extensive amateur background, he was rock solid fundamentally. Best wins were over Hector Lopez, Mendy, Johnson and a narrow win over Murphy that signaled the beginning of his decline. I always enjoyed watching him.