I like Barrera, frankly. JMM was a hell of a lot fresher when they actually fought and he certainly had plenty of trouble with him then
I got to rewatch this fight lately. MAB matches up well with JMM. Both are pretty good combo punchers and counterpunchers. But the difference between them I think has to do with rthym. JMM has a more deliberate and polished counterpunching style. Barrera's is more instinctive, which is why he was able to surprise JMM quite a bit in exchanges (often hitting him at the tail-end of his combinations). I agree this requires a trilogy, with all three being close decisions.