If anything, I'm very impressed with the customer service of In-N-Out Burger. Compared to other fast food places, In-N-Out is by far the best when it comes to providing a family friendly and customer focused atmosphere.
Burgers are great, but surprisingly their fries are disappointing. Not really sure why as they are fresh cut. But even fresh, the fries have a dry texture to them, nowhere near as good as McDonalds. Also, unless you REALLY like onions, don't ask for onions. They literally give you a full slice of onion, which is a bit much for me.
But otherwise, great place for a burger!