Beaches And Cream is our absolute favorite for a great burger and is always our first stop for lunch as soon as we get on property. Our favorite dessert is there too.
Cosmic Ray's burgers were ok, and the fixins bar makes them better. Never ate there, but I've read a lot of good things about the burgers at the Plaza in MK.
Another vote for Beaches and Cream. I love the atmosphere and nothing beats sitting at the counter with a burger and onion rings and finishing it off with one of their awesome sundaes.