We do MM for the FDP every trip. We have always had a great meal there. We have ADRs for August. I love the theming of MM, it takes you away from the hustle and bustle of the parks.
There used to be a seperate menu the package, but that has changed. You can order off the regular menu now. The big difference was that with the FDP you got a flatbread pizza, salad, entree, entree and dessert. Now (if on the DP) you chose one starter.
The big thing to consider is do you want table service or buffet? I've heard good reviews from both places, so it comes down to that.