I've used the ddp many times, I've had free dining twice, and I've paid oop more times than not....sometimes using TiW. For me, free dining is seldom worth it...I've run the figures and only twice did I spend less when using fd.
The original ddp worked fairly well for us...but then they started tweaking it...no more gratuity included, raised the price, took away the appetizer.
So...last Oct, my dh and I traveled to WDW with another couple. We wanted to have some really nice meals since it was an 'adult' trip. We ate at Flying Fish, Yachtsman Steakhouse, Coral Reef, Brown Derby, Artist Point..in addition to places like Akershus, 50's, Crystal Palace. At least two table service meals a day...late breakfast and then a nice dinner. So, I sat and figured, repeatedly, what my costs were going to be. It was about $750 for each couple for the dxddp. Even when we added in the gratuities, it was still less expensive to go with the dxddp than to pay oop. But...ordinarily, I doubt I would find that to be true. It was only because we had a 2 credit meal each night that it worked for us.
Generally speaking??? I find that using the TiW card and paying oop works much better for us.