Hi, pixiedust!
Interesting dilemma! We have done both CL and DP, but at different times, and as we travel in August usually, we had special deals and received both for free. After much consideration and discussion, here's our "take".
We found that CL was nice for the ADRs (we thought we got better seating and service at the restaurants and dinner shows than if we had made those ADRs ourselves, though that just may have been coincidence) and the breakfast offerings (we are no longer interested in eating breakfast at restaurants, as we feel it detracts from our valuable park touring time and is way too much food in the am anyway, so that light continental "free" service is a good option). And we enjoyed the unlimited beverages (coffee, soda, juice). We liked the idea of the appetizers and wine, however, we found that we were only at the resort 1 out of 7 nights to actually take advantage of that service. Other than breakfast, we hardly used the lounge at all. It would have been nice, but just didn't find the time. Since we can make our own ADRs, pick up quick roll or muffin in the am on the go, and purchase refillable mugs for unlimited coffee and soft drinks at a much more reasonable price than concierge, ultimately we decided that if we had to pay for it, it just wouldn't be worth it for us personally. Having said that, if money were no object, pampering ourselves with concierge services would make a beautiful kind of treat. And if we spent less time at the parks, we'd take more advantage of the lounge. How does your family do WDW?
Now our thoughts on
DDP. We thought it was GREAT...for free. We did the math and found that if we had paid for the DDP, we would have made out just a bit better than the "break even" mark over 7 nights, and that was when appetizers and tips were included, which they no longer are. I would make a plan of where you intend to eat and what dishes you are likely to order, and then plug in all the numbers, and see if it makes financial sense for your family. DH and I decided we would definitely accept an offer to do it again for free, but if we had to pay for it, we'd be better off just doing OOP and forgetting about managing the credits and thinking about getting our money's worth. BTW, we LOVE to dine at the nice restaurants, eat TS at least once per day, including at least one signature experience per trip, and found the dining credits relatively easy to manage.
Direct answer to your question, I'd say splurge on concierge; we see more "value" in the luxuries provided by CL services than in the DDP. Afterall, if you pay for DDP and not CL, you CANNOT use the CL services, but if you pay for CL but not DDP, you CAN still enjoy the restaurants you choose!