I don't know if there are many locations outside of Southern California, but it is one of my favorites. I like how they toast the burger buns unlike most fast food places and they also have a secret sauce! The drive thru is also cool. A person with a headset walks up to your car window and takes your order! My mom is a vegetarian but she will have an In and Out burger every once in a while.
Seens like a great place, maybe I got check it out when I have a chance to go to U.S.