M.G.
We've been to Disneyworld a couple of times and had the meal plan. We had the Medium Plan, with one walk up meal, one sit down meal and 1 or 2 snacks. The meal plan is well worth it. It is great to know that one of your meals you won't be fighting with the masses for a table, you have reservations and will be seated. You will have PLENTY of food, in fact don't forget that one of your snacks can be used to purchase water. You can also ask for a water instead of the desert that comes with your walk up meal if you prefer. Yes, that is 2 drinks with one meal, 1 for the meal 1 for the road. You can also hold on to your snack credits and by sovenier snacks at your hotel gift shop (this only applies to certain items).
If you go with the sit down plan start planning, you have to make reservations like 3 months in advance (I'm not kidding!!). I would recommend highly taking the time to go to Ohana, which is in the Polynesian Hotel. Wonderful Hawian food served family style.
Have Fun.
M