We purchased AP's and the DDE card this past summer just to see how it would work out for us. We did not go for the DDP because our DS is 10 now so is considered an "adult" by Disney for tickets and food - but he doesn't eat $38 worth of food per day yet so the DDP was not a good plan for us. Now when he's 15 or 16 and eats everything in sight it will be a different story!
The more people you have in your party the better deal the DDE card is if you eat your meals together as it is a 20% discount and covers up to 10 people at your table. Only you can use it tho - you can't hand it off to someone else in your party to use, like your spouse. If we wanted 2 cards there was an extra charge of like $20 or something to get a 2nd one. Since it was in my name I had to order all of the meals - I couldn't send DH to get in line to get stuff. We are just a family of 3 so the $65 fee for the DDE card is a stretch to recover as the card is not good at a lot of counter service places in the parks - which is where we tend to eat lunches and it's not good on the Fantasmic packages - but it IS good for Character Dining and alcoholic beverages at the participating restaurants (we saved a lot at Boma using the card as we had several drinks with dinner too). Anyway, we went for a week in August and after I totalled up our receipts we saved about $55 with the card on that one trip. So we're still $10 short of "paying for it". Now, that said, we're going again for 4 n. in Jan. and will use it a couple of times and then we're going again next July for 3 n. and will be able to use it a couple more times. Hopefully we'll "pay for it" on our Jan. trip.
The DDE card is an especially good deal if you have a large party, if you drink, if you do a lot of sit-down dining AND if you go more than once per year as it's good for a year. We will get our money back for it - but only because we're going 3 times this year and because we now plan to eat at places that take the card. I just wanted to see how it would work out & if it would really be worth it for us. We are planning an extended family trip for 2009 so it would be worth it on that trip if we eat 1 or 2 nice meals together. With 10 people, dinner at say a place like Boma or The Brown Derby, it could pay for itself in 1 meal...