I did not have a wholely satisfactory experience in SLC when I was there either a few months back myself. That location is decidedly less friendly than many that I have been to throughout the Avis system. Does anyone happen to know whether SLC is franchise or corporate? I would say that the sort of experience the OP related here is much more likely to happen at a franchisee location than a corporate location.

Either way, the customer experience is dictated by management at each location. After all, have you ever noticed how some locations always have a nice upgrade (where indicated) and a smile for you, and other locations never have a nice upgrade and usually have a grumble for you?