Yes, I believe you have to purchase the dining plan as part of a MYW package -- which means you'd also need to have an on-site room and at least a one-day theme park ticket as part of the package.
Everyone suggests that you need to make your ADRs early if you have specific restaurants and/or times that you want to eat. If you try to wing it, your choices of restaurants and dining times might be limited.
Whether it saves money and/or is right for you depends a lot on your eating habits and your touring style. If you want to eat everything that's included, it is definitely a good deal... but it's a lot of food. If you're not big eaters, you might be better off paying out of pocket. The best way is to price it out for yourself (there are restaurant menus posted online) and compare what you'd actually eat with the price of the dining plan.
In addition -- does the dining plan fit the way you want to eat. For instance, with the Quick Service plan, you don't get any table service meals. (If you wanted to eat one, you'd have to pay out of pocket for it.) With the Basic dining plan, you get a table service credit for each night of your stay.
My DH and I spent a long weekend at WDW during
Free Dining and we thoroughly enjoyed the
DDP. However, I keep running it through and I'm just not sure it's a good fit for our whole-family trips. Price-wise, I think we'd about break even versus what we'd spend without the plan (but the DDP would entitle us to more food. We don't normally eat dessert or a lot of snacks.) We usually eat a table-service meal every *other* day when we travel. (The kids don't love TS meals that much. They'd rather spend park time... but I don't want to eat CS for the entire trip either. Sometimes I'd like someone to bring me my food! LOL!)
So... I wish they had a customizable DDP...because none of the ones they have are quite right for our family. I'm guessing we'll probably go without the DDP again!
