I have some pennies on Marquez. Seemed worth the try.
Last I heard, you had to bet $100 to win $10 on Pac, so not much to lose betting on JMM. But really, those odds are fair. Even in his prime, and at a much lower weight, JMM was not as fast as Manny. Now he's older (at 38 he is at an age that is well past prime for most fighters, exhibit A, Moseley in Pac's last fight) and almost certainly slower, and has no idea how much harder Pac hits at welterweight.
A lot has been made about the fact that JMM is such a great counter-puncher. Manny has had problems with that kind of style in the past, which is why their previous two fights were so close. But Manny is not the fighter he was then. Look at the list of opponents he has dominated since his last fight with JMM. Except for the lightweight match against David Diaz, there is probably no one on that list JMM could handle.
This would have been a somewhat more competitive fight at 140, and might have been very interesting at 135, but JMM has not shown he can fight at welterweight. He looked totally lost against Floyd, and he passed up a chance to fight Amir Khan at 140, which could only mean he realized he couldn't handle Khan's speed and size. There are rumors he hasn't trained that hard, that he is only in this for the big paycheck.
I will be extremely surprised if it goes the distance. Manny is ****ed that JMM keeps claiming he won the two previous fights, and has not so subtly hinted that he won't go easy on JMM in later rounds, as he did with some of his previous opponents. The only way I see an upset is possible is if Manny, in his anxiety to score a fairly early KO, becomes overaggressive and runs into a perfect punch from JMM. You can never count out a possibility like that. There is no way JMM is going to win a decision, if he somehow lasts twelve rounds he will be begging for mercy. Much bigger fighters who went the distance or near distance with Manny did it only by running away most of the fight, except for Margarito, who got a broken eye socket for his bravado.
I keep thinking that all of Manny's other interests--politics, singing, acting--have to affect his training at some point, but they haven't yet. Think about this: since his last fight with JMM, Manny has fought a total of 60+ rounds. He has won virtually all of those rounds on all three scorecards. There is I think only one of all those rounds (the first against Cotto) in which all three judges gave the round to his opponent, and a handful of others in which one of the three judges scored it for the opponent.