I didn't get a chance to meet Bernat in person, but communicating with him was friendly and easy. The check in/out process was simple and smooth.
Although the Mission can be a little rough around the edges, I really loved the location of this apartment -- close by some of the best shops and restaurants SF has to offer. It's also just down the street from a BART public transportation terminal.
As another review had pointed out, the neighbors were a little loud on a couple occasions, but I'm fairly certain you'll encounter that in just about any city apartment.
All in all, I'd recommend Bernat's apartment. The place is comfortable, he's easy to work with, and the location is good.