I just did a rough draft to decide if ddp was worth it for me. I am going first week dec so I don't have any discounts yet. With 1 adult 3 kids it seems cheaper for me. We are going to CRT, Boma, chef mickey, ohana and hopefully BOG. Even without counter service factored in it is cheaper for me to do the dining plan. I was hoping oop would be, but I guess it's the 3 kids / 1 adult that makes it less this time.
If you have kids under 10....that's when it the savings start to accumulate. The more you have, the better the plans math works out.
When we were 2 adults and 3 under 10...the DDP worked out very well for us, because we could not buy a CS, TS, and snack, per day, for less than the cost of the kids plan. We basically broke even on the adult side, but saved a decent amount on the kids.
Now, we are 2 adults, 1 Disney adult (my oldest is 10), and 2 kids. It's no longer a good deal for us...because my 10 year old can not/does not eat like an adult. She simply can't consume enough food to justify paying upwards of $50 per day for her meals.
We did our December trip OFF the DDP. By going OOP, we ended up saving roughly $275 over what the DDP would have cost us...and threw in an extra TS meal, to boot. That's because in some places my oldest ordered off the kids menu and in MOST cases we were able to share an appetizer OR desert at dinner with the whole table of "adults". Basically, at most non-buffet TS we were paying for 2 or 3 adult entrees, 2 or 3 kids meals, and ONE app/desert.
Full disclosure: We are DVC members so we do not (unless we want to book a room AND buy Disney priced tickets) have
free dining available to us. Likewise, we typically are in a 1BR and stock our fridge..so refillable mugs have no use for us, either.
It's different for every traveling party. Everyone's answer to the question "Does this work for me" is going to be slightly different. And it's probably going to change, over time, especially if you have young kids.