We had an absolute blast at Go Paddle AZ.
Booking a time was easy, as was getting there. You park in the main lot and wait for little "shuttles" (extended golfcarts) to scoop you up under a big tent - which even has free drinking water! Shuttles run one after another, so don't worry if you don't get on the first to arrive.
This was our first time doing SUP. The employees were awesome - super-friendly - and set us up really quickly.
They have optional baggies if you want to take a phone or keys and keep them dry. I didn't want to risk it, so we left our things in the shop.
Time is by the hour, and you're charged extra if you return past your alotted time slot. If you go out without a watch or phone, either yell at passerbys for the time (did that) or do your best guestimating (didn't want to do that).
They also have punch-cards that can earn you a free visit.
Would definitely come back here!