We always wait to see how close our room is to the food court. I don't want a 5 min walk to get something to drink.
We did buy them this trip, because we were so close to the food court, but actually ended up with some bottles in the room. I got rather sick of fountain drinks, and preferred the bottles.
We got our $$ worth, but it took effort, rather than being convenient. We only ate in the food court three times in 9 days, and we were on the food plan, so drinks were incl. We would fill our mugs w/ our meals, and get bottles of milk, soda, on our meal plan to take to the room for later.
I prefer having a cooler full of drinks in the room. Just my 2 cents, but the $50 in mug cost, for our family of four, would have bought more than enough soda at the supermarket.