They could possibly have the best milkshakes on the planet! They will offer you your choice of dozens of flavors. I had the "Reeces" Milkshake (with chunks of Reeces Peanut butter cups inside...
The Burgers are also very good. They have 10-20 variations on their standard burgers. In addition, they round out the menu with a variety of American favorites.
They go out of their way to make it feel like a 50's diner, complete with old fashioned skirts and shirts, and red lipstick. Great for locals, even greater for tourists.