Yes it does. I've done tons of research, punching in the exact prices and comparing it to the dining plan cost. It's pretty rude to imply people who disagree with you haven't researched.
It absolutely does save money if you would eat similarly to the dining plan without it. Comparing the cost of the restaurants to the cost of the DDP, we save about $250. I know that number is inflated because of the items we wouldn't order otherwise, but even taking out QS desserts, we still come out ahead. Everything else is similar to how we would order. There is a slight savings there. The sticking point is you'll save money if you would eat the same on the dining plan and off. Almost all of our meals (I think there's only 1 for upcoming trip that isn't) are buffets or family style. They are where we want to eat, we're not eating there because of the DDP. We can't eat at those restaurants on the cheap, we can't cut out a dessert, we either go and pay the full price or don't go at all.
It is much harder to save money with the DDP than it used to be. If we weren't getting it for free this trip, we wouldn't be buying it even though there still is a slight savings for us. We'd opt to eat at cheaper restaurants or do QS for some meals, because of the outrageous prices whether you're paying OOP or using the DDP. $58 per person per night and $45 to eat at a character buffet are both lots of money.
Again, the determining factor is whether or not you would order the same OOP. For years before the dining plan came to be, we ate exactly the same at Disney. For our family it can save money, but I do realize we are not the norm.
The problem with absolute statements is as soon as you make them someone usually comes along and tells you why you're wrong, it's basically an invitation
