Every location of In-n-Out Burger I've ever visited in AZ and CA has been the same: shockingly efficient, Stepford-like teenagers politely fulfilling my desires for meat and potatoes. The food is also always good. The burgers seem like they are actually made of meat instead of mystery fillers. The fries are crispy but not in an unnatural way.
Make sure you are aware of the not-so-secret menu. I usually get a burger protein-style, animal-style, with mustard instead of spread. They get it right every time. Just went there yesterday with out of town family guests and they love the place, too. It is a priority whenever they visit.
The location at Desert Ridge can get kind of busy, but they always get you through the drive-through line surprisingly quickly. I opt for drive-through when the place is busy, as it seems faster than when you order inside. Plus I am not a fan of smelling the ketchup-permeated air that fills the restaurant. Americans. We love our freaking ketchup.