I get the deluxe plan every trip to WDW, and have always found value in it...though the first year I didn't completely understand it, and that it was a credit system that could be shuffled around how you see fit. I thought you had to use breakfast credits for breakfast, lunch for lunch, and so on. Anyhow, in 2010 a lot of TS credits (even though with Deluxe they are ALL TS credits) went to waste. However, though that year I didn't crunch the numbers...we did CRT twice, Akershus once, and many other restaurants. I'm fairly sure it was a value.
In 2011, I also found it a value, traveling with a 10 year old who eats like a horse, his sister (my kid's mother), and the kid. The 10 year old qualified for the Adult Menu, and while it was a lot of food, we didn't stuff ourselves. We just all ordered something different and stole bites from each other.
This was a lot of fun, as we could really get a lot of variety at the restaurants we chose to dine at. Appetizers and meals I may not normally order, because I'm unsure about them, then became an option to test out.
In 2012, I *did* pay very close attention to the Dining Plan cost, including snapping pictures of receipts at the end of meals so I could add them all up, and I came out a few hundred ahead using the plan.
This year, I'm going to write it all up into a spreadsheet and see how close the estimator comes to what we really end up paying (including gratuity and adult drinks) and do it as part of my Trip Report...simply because I'm curious.
With respect to those who say it is too much food, I would agree. It is a LOT of food. The 1 QS, 1 Snack, 1 TS Dining Plan is much more reasonable than the 3 QS/TS, 2 snacks of the Adult Plan. However, we don't stuff ourselves. The question would be, if I want to manage a food budget while there? I don't. I like having it pre-paid, and the convenience of it.
Leftover snack credits at the end of the trip I use up at Goofy's Candy Company to buy various treats for co-workers and family members. Everyone loves Mickey Rice Crispy Treats at the office!
All that being said, it really is up to the individual, how they eat, how they picture their vacation, and what they are willing to pay for.