When you come to this location expect delays. It is usually busy on any given day, and during snow-bird season it's pretty busy. The parking lot is accessed from University Dr, and depending on the time of day it's a nightmare trying to turn in. Sometimes you need to get your Arizona driving balls ready in order to turn in here. There is a separate lane for the drive up mailboxes. There is ample parking in the lot.
There is a large area in the lobby where the P.O boxes are located, and through the doors is the main part with the counter and supplies. Usually they have 2-3 people working at a time. They will have someone come from the back to check if someone is there to only pick up packages or held mail. That usually helps the volume of the line. I've never experienced bad customer service here, in fact all the workers that have helped me have been pleasant and helpful.