I believe that De Rossi's Roma would stand more chance against Milan. They failed with Mourinho against them. They lost twice in their domestic league. However while there is good progress in Roma football I'm more expectant from them. Because above all else they have started to play an effective attacking-oriented game. 
This was what Roma needed. Mourinho was just placing obstacles ahead of Roma because of his boring defensive strategies. Roma aren't a good defense team. We must have all understood it so far. They need to play more attacking to balance themselves.
Milan are still a tough opponent but Roma have more chance to advance after some important changes made by De Rossi.
I agree that Milan has a better chance, but I am not underestimating Roma neither, looking at how they have been since De Rossi came in, I think that is why it is going to be quite good and will make a lot of people money if they bet on Roma and turn out to be right. This is of course not easy, we are going to face a lot of trouble if we are not careful so we should definitely consider the situation to be highly sensitive.This was what Roma needed. Mourinho was just placing obstacles ahead of Roma because of his boring defensive strategies. Roma aren't a good defense team. We must have all understood it so far. They need to play more attacking to balance themselves.
Milan are still a tough opponent but Roma have more chance to advance after some important changes made by De Rossi.
If you bet on Milan, you are betting on the better team to win the game, so you are making a right decision, if you bet on Roma you are betting on the team that made a comeback and gained a momentum so that's right too. Considering game by game, I think betting on home team winning in both cases could be fine.