The selection of the room is critical
I have stayed in this hotel a couple of times. 
Location: no question this is the one of the best location in San Francisco as it sits near Union Square. If you drive rental car to the hotel you could return it just to the opposite as more rental cars have their return office there. There are many restaurants around the area and you could just use Yelp to search. you would always find one to fit your stomach. 
The room: It really depends on which tower you would stay. try to request a room in tower 1 which has big room and good facility. This time in June 2012 I was allocated a room at tower 2. you have to walk a long way to reach the lift and the room is very small. The toilet is also very small and I could not believe it is for a business type of hotel. 
The facility: It is very strange that the room on the tower 2 does not have refrigerator. there is a cabinet which obviously is for fridge before but is locked. I called the service desk and was told a one-time charge of $15 will be put on the bill if I request one. The room is so small that there is only one chair and no sofa at all. I went ahead to have requested a fridge and they brought it and just put it outside of the cabinet. Anyway that one-time charge did not show on my bill.
The service: I would say the clean service provided by the hotel is very poor. They hired quite a number of old Chinese and Mexican ladies (60+ years) who does not speak English very well. They do not clean the floor and just came in the replace the towels and trash bags. Every time I have to call them to remind them put in the shampoo, tea bags and coffee cups. They would not top up if you do not ask. 
Overall I think their service is really a big problem. If you choose this hotel insists to have a room in tower 1 but not tower 2 &3.