The refillable mugs are worth getting if you are staying more than 2 days! We got our money's worth! Each mug costs $10.99. If you buy a soda by itself, it is $2.50 for a bottle (not sure about fountain drink, over a dollar though, so it adds up!) There are two styles of mugs - one will fit in a cup holder because it has a smaller bottom, the other is fatter all the way down. They have them on a stand at the end of every cash register where you check out at the food court. You just grab one the first day, take it to the register, they clip off a tag, you pay and start using!
You can get soda, coffee and hot chocolate (tea too I think - I just never had tea). My favorite was the mixture of coffee and hot chocolate in the morning! The only thing you couldn't get was milk or juice (or alcoholic beverages!).
One note - I had to point out to several people that there are also small creamers and lemons in a "refrigerator" at the front of the line (on one side only I think though) and a "non-dairy" creamer in a metal container by the coffee pots. I mention this, because it seemed that I would be getting my spoon or sugar in the morning, and invariably someone would ask me where I had gotten the cream.
We had a cooler in our room with soda and water (we had driven and had packed it full), but we ended up using the mugs almost exclusively while at the hotel. I carried my coffee with me every morning to the parks and after I finished I rinsed out the cup at a restroom and stuck it in my backpack.