If I'm waiting for a layover (or just leaving) CLT and I'm on US Airways in Terminal C, this is my restaurant of choice. The food is better if you sit for table service, but at least they have a fairly quick (15 minute - 20 minute during rush time) if you do the take-out window.
They have a some good burger choices. The chicken burger options are good too. Between the fries, sweet potato fries, and tots; I would recommend you go with either the sweet potato or tots.
The burgers are pricier than other burger options in the airport, but I find the quality better for the turnaround time than going to a Burger King, etc. The price with a soft drink and fries is usually in the $16 - $20 range, and for the type of meal in the airport isn't outrageous.
The wait staff seems somewhat distant but I'm usually stuck flying late afternoon so I don't expect the most cheerful people. The reason to eat here is the burgers. They do have a bar so if you have more time to kill and aren't urgently trying to make a flight I recommend you dine in for a better burger