How old are your children? Under 3 is free, and 3-9 is only $11/day. Those are a deal no matter where or how much you eat in WDW.
Do you like table service meals daily, or character meals?
DDP is the most cost effective way to do this.
I was NOT going to do DDP. DS12 is "adult"...I KNEW I could feed a family of 5 for less than $140/day! But DM said, yes, but not without a lot of effort..nearly exclusively eating at counter service, sharing meals, saying NO a lot. $10pp for a counter service meal is fairly average.
So now that we have jumped in, I am SOOO excited. I love that we are having a 'real' meal daily--and able to order WHATEVER we want from the menu, not looking at prices as I usually do. My kids are good eaters, and the younger 2 will eat almost anything. DS12 looked at menus and decided he could find something everywhere (or DD9 could order from adult menu and he would order from kids!) Kids can get a special treat daily...dessert from dinner could be the next day's breakfast

I love that that expense is already paid for, and I love being able to say YES to my kids...YES you may order a smoothie instead of water, YES you may have dessert at lunch AND dinner EVERY day, YES you may get a Mickey bar EVERY day!!!! The convenience as well as the many options are what drew me. Could I do it cheaper...probably, but not MUCH cheaper.
We are bringing breakfast bars; will pick up milk, OJ & coffee to breakfast in room most mornings. If we find we are sharing lunches, we may grab some breakfasts, too.
There are many who enjoy DDP for many reasons (convenience, variety, a "good deal", if in perception only). Others feel it is too much food; some feel obligated to eat it all. Many have said the cost is a wash...they really didn't save any $, and they certainly would not order that much stuff. Some do not like needing to have reservations, and having to base their day around them.
I have enjoyed reading restaurant reviews & menus to find where we will eat. I am a foodie, so good food is a big part of a vacation for me. And I am eating at places we would probably never pay out of pocket for.
SOOOO excited! 18 days!