Hi there, We've had the free
DDP twice and paid once for it (2 adults 2 children 3 & 5yrs now). It was great for free, who wouldn't take it, but we have said that we wouldn't pay for it again.
The problem that we found was that with having to book your reservations so far in advance you are committing to being in certain parks at certain times. It becomes very restricying and you can't 'go with the flow'. Sometimes if it was early morning park hours say in the Magic Kingdom and the girls were up really early we would want to take advantage of that but we'd find that we had a midday reservation at Coral Reef in Epcot! We endede up cancelling so many the day before because our holiday was being so dictated by lunch reservations. With young children we found that they were so exhausted by the end of the day it was pointless booking dinner reservations. In the future when the children are older I would definitely consider it again as we could book more reservations in the parks or different resorts for the evening when they could stay awake longer and enjoy it.
We also stayed at POFQ & PORS and ended up back in the resort on most evenings (due to tired little people) and enjoyed walking between the resorts and mostly ended up with my husband and I using up our dining credits in Boatwrights in the evening at Riverside, whilst the children slept in pushchairs next to us.
The childrens menu is also VERY limited on the dining plan and they soon got very bored of it.
The one great thing about it was being able to use 2 credits to book the Royal Table which otherwise is VERY expensive for a family and to use for character breakfasts.
If you're willing to drive offsite then there are some much cheaper options in lake Buena Vista which only take 10 minutes max and give you a great deal more freedom and a more relaxed holiday. If you are planning on eating in parks and reorts it would work out cheaper to purchase DDP.
Obviously this is only my opinion but some of this info may help you a little.
By the way I've just noticed where you're from, I grew up in Hempsted!!!
Have a great holiday whatever you decide.