I have done the DDP a good handful of times thinking I was saving money and for the convenience of having everything paid for. However like others have said, I wasn't really saving money. I am not a huge sweets and dessert person, that being said there are a lot of desserts at Disney I do like and I find myself eating them even though I'm beyond stuffed simply because I've already paid for them! I hate the idea of ordering meals just to "maximize" the plan. There have been times I've wanted a simple chicken dish or pasta dish but I won't order it because then I'm not "utilizing" the plan correctly. I've told myself a few times that i'd buy the plan and not care about the price of what i'm ordering and go with what I want, but in the end my frugal side takes over and I get something I don't want. I feel like I spend so much time researching menus to plan where we will eat and what snacks we will get.
I actually sat down and spent a few hours making a sample meal chart according to what park we would be in and what meals we would most likely order and I can say that it came out that the meal plan was more expensive as we don't do dessert and usually share snacks or bring them into the parks with us. It wasn't a huge savings, maybe $100 for myself and my two kids, but it was still a savings.
We go every year for 2 weeks and I can honestly say i'm kind of tired of Disney food so I tend to make most of our meals at our hotel. I save a boat load of money and feel like we are able to eat healthier. We have always done breakfast in the room (cereal, bagels, toast, fruit, granola bars) as I just bring the dry goods with us and then get the perishable stuff there. And then we eat at a few of our favorite places: Boma, Crystal Palace, Norway Princess Dinner and then one other table service and then a couple of counter service meals. I bring a snack bag for each kid with me that they pick out in the morning and then we will usually get something to share at the parks: funnel cake, popcorn, huge sundae.
As a side note, I always book our first night separately and do purchase the Deluxe Dining Plan for that night. For one adult and 2 kids we are able to get 3 table service meals, 2 snacks and our resort refillable mugs each for about $140. Because my kids are kids it does save a boatload of money as we are able to get in our favorite meals, just bites that we have to do it in the first 24 hours. Now once my oldest is no longer a "kid" it will not be worth it and that will happen next year.