Bad if you use regularly, fine for short-term
I use this facility to store furniture donations for a few local orgs, so I'm in it several times a week. I think your experience will depend highly on where in the facility your unit is. I was in a building lower on the hill, and though I was paying for climate control the air conditioning barely worked. Also there was some kind of leak and the hallway would have a giant puddle of water in it every time I came for two months. The owners wouldn't fix the leak, so the workers had to just go vacuum it up every day, and if I got there in-between vacuumings I would just have to either take the long way around or drag the furniture through water. It always smelled mildewy. Also parking lot is inclined all over the place, so if you use a cart be ready for it to roll down a hill when you're not looking.
I rented a larger unit in the main building, and the AC does work in there, and the incline is less of an issue. My only problem up there was that the worker forgot to take the company's lock off the unit after I rented it, so I couldn't use it the night I got it which was hugely inconvenient for me. I called to complain and the worker just apologized and didn't offer any kind of compensation, so I guess don't expect to be taken care of if there are problems.
Conclusion: if you need to keep some stuff there for a month between moves, sure it's fine. If you need to use the unit regularly, I think there are better options. Next time I upgrade units, I'll be looking elsewhere.