Snowglobe girl...
My DH and I have done the 3 meals a day and the 2 meals a day ones, last year decided not to add on any meals. The problem with the 3 meals a day is we became a slave to our meals, wanting to get the most out of our $'s spent. We actually got to a point where we would look at each other and say "OH NO! It's time to eat again!" It was a fabulous experience eating at all the great restaurants, but it was overkill. The 2 meals a day was better, I love the big breakfastes and a nice dinner, we would then snack at lunch time. Last year I did a cost analysis. I looked at the menu's of where we wanted to eat, selected our meals, found out the cost... then decided we actually would save money going without the plan. I would suggest
1: decide where you want to eat
2: get the menu's from those restaurants and decide what you are likely to order and the cost.
3: compare the cost of adding the meals ($500) to the cost of what you would order without the plan.
Remember, even with the plan you will still spend money on drinks and snacks. Be sure to compare the apples to apples! If your plan pays for 1 snack, 1 counter service and 1 table service a day then compare that to where you would get your snack and it's cost, where you would get your counter service and it's cost and where your table service would be.
Hope this helps... And have a great trip!