I used to live in Tucson (at least one of the Costco's there is reportedly one of the nation's busiest) and I never felt like the shopping experience there was quite as inconvenient as it is at this location. It's a Costco, a warehouse, I get it, but it's too small.
I won't even attempt to go there on a weekend because the checkout lines stretch far into the store! The first time i went there I asked another poor soul (also stuck in a excessively long line) if that was normal, she managed only to nod. It's a question as old as the hills, but they in world would you not have every single available checkout open-for-business on the busiest days of the week?
It could just be my perception, but it seems like they have less stock than other locations.