It depends on the hotel you choose (and the level of the meal plan). There are 3 levels, if you book the DLH you can only pick the highest level meal plan, but you can upgrade from the others. The lowest level only gives you buffets, the highest also the diner show and character meals.
My advise is to pick the restaurants you want to eat at and then do the math, for us it's never beneficiary to get the meal plan. (but that when breakfast was still included in the hotels (or we got a club level room), so the value got a bit better after that).