I don't consider them much of a perk and I doubt I would purchase one on it's own if I weren't getting the dining plan. But since I do get the plan, I do use the mug a bit. We fill them in the morning on our way to the parks to drink on our drive and then just leave them in the car and fill them up again on our way to our room. So usually 2 refills a day, sometimes 3. Over 10 days it would pay for itself, but still not a big enough perk to buy it outright. We don't spend a ton of time at our resort, although if you did that would really up the value.