I am somewhat new to In-N-Out phenomenon (the last couple years). As far as fast food burgers go, In-N-Out is as good as it gets.
Last year I was in Vegas for the college hoops tournament. One evening we made a planned trip to In-N-Out. The cab driver was shocked that we were all so excited to go to a fast food burger place. Coming from the east coast, it is a mini-tradition while in Vegas. If you have a local In-N-Out you just wouldn't understand -- we don't have that luxury.
Somehow, even with all the hype, In-N-Out lives up to expectations.