I'm not a fan of the DP, or the free DP promotion. But that's because of my eating habits. I don't order dessert with every meal, I don't get more than water to drink at every meal, and I rarely snack. So the DP doesn't save me any money. It would only be saving money for me if I normally ordered all those things. Plus, I hate the inflexibility of it. I don't want to worry about whether or not a restaurant takes the DP and have any restrictions on what I am able to order. I also frequent the signatures, which makes the DP an even worse idea for me.
You have to assess what you would normally do and the cost of it before you know if the 'free' DP promotion is a good deal for you.
I say 'free' because you pay rack rates for the room. If you decide the DP is not a good deal for you, then a percentage off the room rate is a better deal. I always book room only with a percentage off. I also am a passholder so I have a TIW card, which gives me 20% off at most TS locations. It fits my eating habits much better than a DP, so I save a lot of money using the TIW card.