Mmm... That is a tasty burger. Skip In-N-Out (overrated), come here. And any place that allows you to put a fried egg on your burger is obviously going to be good.
Aside from being the cheapest burger on The Strip (or even the cheapest food), it is just darn fun and good. You hear the workers yelling out orders, it is a small diner-like atmosphere, and the burgers just taste good. Skip the lettuce and tomato and such and opt for egg, onions, bacon, and all the stuff that will slowly kill you as you walk back to your hotel.
And for the little ones -- like my wife who doesn't eat a ton -- they have small burgers that are perfect for little appetites.