My girlfriend and I try to get the last ADR of the night when we can. We find that the service is usually better when we are one of the last tables. The wait staff is usually more calm and relaxed since their day is almost over and they don't have to worry about as many tables at that point. The food does not suffer at all from a later ADR, even with buffets. But the best part about having such a later ADR in a park, is the walk back to the busses after the meal. It is very peaceful and beautiful and at the same time a little creepy walking through a park with just about no one else there (besides people cleaning and others who have a later ADR). Take the time to get some great shots of the park without anyone really in your way.