It's a very subjective question with a very subjective answer, I'm sorry to say.
What it boils down to is, how do you want to spend the dining portion of your vacation? If you're going to (or at least want to) do a sit-down meal pretty much every day, then basic
DDP might be a good fit. If you like counter service meals, then the QSDP might work. If dining is a big part of your trip, DxDP is an option.
As for the "amount of food", no one is forcing you to order everything you're entitled to. Skip the dessert f you like (or order fewer, and share). There's no need to "maximize" value of the plan to get good value from it; as long as you aren't the type to always order from the "low end" of the menu, you'll probably at least break even, and do so without having to worry about prices, etc., during your trip.
All that said, the most important question still remains: do the credits allocated for a specific plan fit in with the way you want to vacation? If so, then I think the dining plans, across the board, are a good deal. If not, then I would suggest simply paying OOP.