We just signed up for one for my daughter in college. We have a 10+ hour drive from your college - makes it much easier to not have to get the roof top storage to bring all her stuff back and forth. We shared it with several of her friends so it is like $40 total for them to have for the summer.
Some of the units you rent are air conditioned, some are not. You pay accordingly - since the only electronic items we were storing were mini fridges and it is really just dorm stuff, we went the cheap route.
While I was there helping them move their stuff in - there were several units that had this extra lock on it saying they were overdue and they needed to settle with the front office before they could get their stuff. So I can see this happening where people get behind in the payments and just leave their stuff behind.
The unit we rented was within the building itself - smaller size - that you use a freight elevator to move your stuff to the higher floors. They did have some of those other single ones - that look like garages there as well.