A counter-point to the mug program. The mugs are great if you want them as souvenirs when you get home, but for the drinks alone I don't think they are worth it. The three biggest negatives are: 1) Depending on where you stay, the food court can be a long long way from your room so they're only convenient at meal times, 2) If you're not a fan of Coke products, you're outta luck, 3) When you've got 4 or 5 in your family the cost adds up.
We usually have a car with us, so we now stop on the way to WDW and buy several cases of the drinks we like for a small fraction of the $50+ it would cost to buy mugs for my family. The drinks are in our rooms and easy to access.