Yeah, it's a little overpriced for burgers but it is not out of the norm compared to other joints like this ie; Coal Burger, Modern Burger, etc...
We have eaten here two times. Both times I ordered the Zinburger sub the veggie patty and add truffle aioli. Both times it was great. I will admit our first visit we each ordered a side of fries which was way too much food. One order is enough to split between two people. The milkshakes are stellar and are alone worth the trip to Biltmore.
Definitely expect a wait if you go during the weekend. Other than watching others get to eat before you, I have no complaints. Good service, good food, good restaurant!