I really believe that the DDP is personal preference. I've done it for all my trips and figured what works best for us. The first time it included apps, desserts and tips and was great, but I was a newbie an underestimated how important those ADR's were!
The next trip (jan 11) DH and I did the reg DDP and lost money, as we left with unused credits due to an early (unplanned) departure. In addition we wanted salads and not necessarily desserts with every meal so we had OOP costs. Our other issue was DH loves breakfast and I'm happy with just a yogart or bagel. More OOP. The OOP added up fast. We do drink water with all our meals, but learned to ask for ice water with the meal and a bottle of water which we saved for the parks.(QS)
Now in june and nov we went deluxe and came out ahead. Planning out meals around the parks wasn't so bad in june because:
1. We used park hoppers (another personal choice)
2. We did a split stay and only did the plan 5 out of 10 days, so we still had plenty of flexiblilty. (the other meals were crockpot meals that were ready to eat when we got back)
3. We ate breakfast (usually character meals for DD) snacked for lunch and then a sig TS for dinner.
In oct it was more of a hassle as we were there only for halloween weekend. We ended up cancelling a few ADRs, but still came out ahead because of the signature meals.
DD9 isn't yet a disney adult, however I think I'll be very careful deciding on the plan for our next trip, as by then she will be.
The best part of the plan for us is the following:
1) prepaying everything but those pesky tips (I thought I was prepared in june, but still had a little sticker shock

).
2) we ate at restaurants we'd normally skip due to price
However, if i could only do DDP or QS plan, i'd probally take poptarts, ceareal, etc for breakfast. sandwhiches for lunch and pay OOP for TS or use my crockpot. On the DDP there are too many QS for us, and eating the QS is harder to plan for me, as we just aren't the type to enjoy meals that have fries with everything. We end up wandering around the different parks saying when we get close to .... will eat there because their menu is better...Then we're all grumpy and hungry....not happy
so the dining plan is like everything else, what works for some, stresses/or doesn't work others... think AP's, park hoppers, TTW card, etc...
What i think some people forget is that while we all love going to disney, we all do it a different way...Our own and enjoy what we do.
(The only people that don't enjoy it are those that go unprepared IMHO).
Our family looks as each trip as a new adventure and tries to stay somewhere different, and eat at different restaurants, and do different things each time.
My bother and his family will only go @ Christmas time (I personally think they're crazy for that one

), stay at the same place and eat at nearly all the same places...
My friend has only gone where they stay off property...
To each their own as DH says...