Extremely inexpensive ($20/month!), and a good customer service experience. But I'm nervous both about the sanitariness and the security.
I wish there had been more metal between my stuff and the outside world.
Also, the first unit they showed me contained dead mice.
Less importantly, there's no elevator, so expect a workout getting your stuff upstairs. But on the plus side, perhaps that's a security measure -- if it was a pain for me to get things up there, maybe nobody will bother getting them back down.
Final gripe -- no automated online payments, so I have to remember to write a check each month. Not the end of the world, just don't move in here thinking you're booking the Ritz-Carlton.