I stayed for 3.5 months and thought it was great! The other people were young professionals from all over the world and everyone was friendly. There was a weekly professional cleaning, which was great for keeping the place in good shape.
The best part was the location. Most interesting areas were within a 20 minute walk: Chinatown, Japantown, Embarcadero/Ferry Building, Fisherman's Wharf, Fillmore, and the list could go on...
Only downside was that the room was small, but hey, it's San Francisco...
Great place to stay if you want to try out being in SF, or if you're transitioning to a more permanent place. :)