I think betting on Mario Barrios is more reliable.
Watching some of Manny's training videos actually convinced me that he won’t go down that easily. He's old, but he's clearly on a mission to prove that age is just a number. In fact, he even gave a guarantee to fans who are worried about his comeback, saying that he knows his own body and understands exactly what he's doing.
So , just for fun, I think I’ll take a shot and bet on Pacman to win ..either by decision or KO.
Two different outcomes, two bets. Why not?

Pacman is the only champion in 8 weight classes and definitely one of the best boxers of today, so even at 46 he can knock out many more boxers and his training is impressive.
Nevertheless Freddie Roach was against such a Pacman comeback and considering their long-standing partnership you can definitely say that he is worried about Pacman. In addition, his opponent is not just average boxer, but still a champion in this weight class and it will be more difficult to knock out such a boxer than a passable opponent.
In general, my heart would like to bet on Pacquiao, especially on a beautiful knockout, but my mind says to bet on Mario Barrios.
You would be having that kind of confusion because whenever our mind and emotion/heart is totally that having that opposition then you would definitely be having that kind of confusion on which it would be that so hard for you to make out such decisions because you would be having those second thoughts whether you should be betting on Pacquiao or with Barrios. Lets just that accept the fact that there would be that deterioration when it comes to human body. Lets say that you are a boxing legend but it doesnt mean that you would be that the same when you are that on your prime. Its already obvious and evident when it comes on his fighting even on just that looking into that recent exhibition fights on which Pacquiao did even though its a bit mismatch with that because of height but you can see the sluggishness when it comes into those punches. For the current age of MP then it is that old on something on a sports that involved body beating. For Freddie Roach then its normal that he would be that having that concern towards MP's health.