Inn at Union Square is a small "boutique"-style facility, of which there are many in San Francisco. It's similar to the small, older hotels in European cities. Our room appeared to be recently renovated/refurnished (given the age of the facility), and the small common areas on each floor are clean and neatly furnished. Overall, we enjoyed the facility and thought it a very good value. The location a block from Union Square is fantastic for access to the heart of S.F. But there were a couple small glitches.
First, the breakfast provided is minimalist (coffee, yogurt, bagels and some small pastries). The $20/night "amenities" fee that the hotel charges, on top of the listed room price, is in effect a "nuisance fee" that allows their advertised room prices to be $20 lower than the "real" price you pay.
Second, our bathroom was clean with relatively new fixtures that worked well. However, the back of the sink cabinet is about 1.5 inches from the wall, and small items such as toothbrushes, soap bars, cosmetics items, can easily fall into the crack and be extremely difficult to recover. A toothbrush of ours fell behind the sink, and in recovering it I dislodged 3 bars of soap, two additional toothbrushes, and a number of small toiletry packets lost by previous occupants.