Had to stay here for one night before my conference at Moscone West started and was thoroughly impressed with The Mosser. Rooms were small but clean. The rooms were also well equipped with a lot of little things - toothpaste, shoe shine, shampoo, towels, bathrobes. Bathrooms and showers, although shared, were very clean.
Staff was VERY nice. I had to print out a ticket for someone and ask the desk if they had a business center - they said no, but they would gladly help me print it at the front desk! Free wifi all over the hotel (this is in comparison to the conference hotel I stayed at - the Marriot Marquis across the street - which made me pay for in-room wifi!!)
Only complaint is there is no A/C (which is fine in SF) but my room faced the back, which had a very very loud vent downstairs so I had to close the window and the room got a little stuffy. Just ask for the rooms facing the office buildings.
In terms of location it's close to the subway and walking distance to the cable car rides. Perfect for travellers!
Would recommend this for young travellers on a budget, or those that need to go to the conference at Moscone West but is on a tight budget.More