We used to have a storage unit with Storage Max. Storage Max has an EXTREMELY rude staff, from our experience. They do not accept credit cards and will only accept checks or cash. So do not even think of setting up an automatic payment plan. Also be aware that your belongings may be exposed to some dust from dust storms, as ours were. Which never happened in our previous experiences from renting storage units.
The prices are the cheapest you can find in Scottsdale, and the saying was true to us, remember, you get what you pay for.