I was in San Francisco on business and added a weekend to see the sights. I stayed in a private room with ensuite shower on the fifth floor (6 nights). I have stayed in many hostels, but this was my first hostel in the US. I was pleasantly surprised by the size and cleanliness of my room and the hostel in general. My room had a queen sized bed which was very comfy, a desk with chair, a lounge chair and a good size bathroom. An extra bonus was the built in wardrobe which allowed me to unpack all my stuff and store any valuables. Bring a lock if you want to lock the closet door for extra security.
My room was on o'Farrell street and although quite noisy during the day and early morning I found it didn't bother me at all for sleeping. I expected more noise coming from within the hostel, but perhaps due to the location of my room or maybe the hostel wasn't full, but I found it to be very quiet.
The shop next door is very convenient for drinks or snacks and there are plenty of places to eat in the vicinity.
The event I attended was at the Hilton, which is right across the street. Didn't mind at all that I opted for the cheaper hostel over the expensive Hilton...