This Sept. will be our 5th trip using DDP. First time (Jan. 05 we paid for it) then we had it for free in Sept. 05, 06, 07, 08, and now 09 Oops, I just noticed that we'll be using DDP for the
6th time this Sept.! Wow, I didn't realize that!
Of course, I prefer getting the plan rather than paying for it.

My DD is turning 10 while we are there and she'll be an adult according to Disney. This makes me very happy as she can now order whatever she wants and if she wants a kid's meal (and she's already told me she will) then I will pay OOP for it and pocket the adult TS for another meal. I see several 2 TS in our future!
That being said, if I had to pay for her, as an adult, I wouldn't do it. There's no way we would spend $120 (plus tax) at day for our 11 day trip. That's $1320 Yikes!

Maybe I would get the SQ plan, but even at $990 for the 3 of us, it's a little pricey.
When we bought the plan in Jan. 05 it was brand new and still inc. appies and tip. What a deal! Now it's not as good.
I do agree that having to schedule ADRs to take advantage of the free DDP can be a little cumbersome but eating at WDW is worth it. If we aren't on DDP while there we do change some of our eating habits. Though not all.
On DDP --------------------------------No DDP
Breakfast in room----------------------------------------Breakfast in room
Buy refillable mugs(nice souvenir)-------------------------Buy refillable mugs
Share meals---------------------------------------------Share meals
Order desserts------------------------------------------ Hardly ever order desserts
Snacks galore-------------------------------------------Very few snacks
Eat almost all meals at WDW-----------------------------Eat more meals off site
Counter service breakfastto spend credits at end of trip----No counter service breakfasts
Sit down breakfast last day-------------------------------Finish up breakfast foods last day
Eat leftover desserts in room------------------------------No leftover desserts
Use CS and SC at waterparks-----------------------------Bring own food/beverages into waterparks
Let DD9 order whatever she wants!-----------------------Restrict DD's menu choices.
Stop at
Walmart for fruit/snacks/diet coke/water----------Stop at WM for same
Eat alot-------------------------------------------------Eat less
Try new restaurants-------------------------------------Stay with same old favorites.
So for us, it's not a huge difference, but I definitely wouldn't pay for it, especially now that DD is an adult(with a kid's appetite!). One reason is we don't spend all our time at WDW. We check out the "Real Florida" beaches, etc. That means there are days we don't go in the parks. It's one of the reasons I make alot of our ADRS at resort locations, not in the parks.
If I was to consider paying for the DDP, I would probably split our stay between resorts (something we used to do prior to free DDP). That way we could use DDP for part of our trip and be on our own for the rest. Maybe 5 nights at one resort with DDP and then 5 nights at another resort without. We used to enjoy splitting our stays.