(It also has a secret menu for those in the know.)
The ingrediants are fresh, never frozen. When you order fries, they slice a whole potato. The bread is fresh-baked.
The company has a strong social conscioncious--They pay their employees far above the minimum wage and offer benefits to many of them. They even received a fairly positive write-up in Schlosser' book Fastfood Nation.
So, basically, In-N-Out is the fast food version of heaven... it's just a lot easier to document that the theological one. (I believe that they are a Christian-owned company, so this is an apt metaphor).