Very easy and pleasant experience.
Renting a unit was so easy... no surprises... it was a snap. The web site explains (through pictures and words) what household items commonly fit into each, different sized unit. The web site further explains all the unit monthly rental fees (and discounts!), insurance requirements and required paperwork (which can be filled out beforehand on-line) so there was no surprise when I rented. I brought my own lock to use, but if you want, Uncle Bob's has locks you can purchase.
This was an overall excellent experience and the prices were the best for the area. I highly recommend using Uncle Bob's.