Multiple trips? I'd vote TiW. One trip? DDP.
I would say: "One trip? Cash."
We eat what, where, and when we want. We aren't the types to worry about menu pricing. If I want the steak, I'll order steak. Every trip---every single time---we spend less than or about the same as the "appropriate" DDP would cost. Usually, that's because we don't eat exactly the "right" number of TS and CS meals. But, even when we hit the number on the nose, cash still works out better because we inevitably mix in different kinds of restaurants. Some of those would have been good deals on the DDP, others not so much.
So, when you average it all out, DDP wouldn't save me money. Perhaps even more importantly, I don't always eat the "right" way. For example, I will often have an appetizer and entree at a TS meal, waiting to have something sweet later that night from the confectionary, etc. Cash is more flexible than DDP credits, because you can buy anything with cash.
If you have more than one trip in your TIW window, the TIW probably saves you some money. But, less than you think. People think of it as 20%, but the card costs $100. So, if your non-discounted bill is $1500 over the lifetime of the TIW, you save $200, not $300, for a discount rate of 13%. As a
DVC member, some of those meals would have been discounted 10% (or more) anyway, pushing the marginal savings even lower.