non smokers go elsewhere
First things first... I will never stay here again nor will I ever suggest it to anyone and that is based on one very specific situation.
My friend and I arrived at the hotel close to 11 pm. When we booked the room we indicated that our flight arrived around 9 pm. I also indicated non-smoking as the first room request item and I indicated again in the 4th spot. 
When we arrived at the hotel we were informed that they didn't have the non smoking room that we booked. They only had a smoking room. He then went on to tell me that they over booked and decided that the last one in would get the smoking room and we were the last ones in. 
This is happening at 11 something at night after my friend and I just had a long flight in from the East coast and a full day at work. Last thing I want to hear at what was close to 2:30 am to me - is that they don't have a non smoking room. And it's because we were the last ones in. He then after seeing how annoyed I was offered a pathetic $20 credit for that nights stay. I was too tired to argue and just went to the room. They did mention that we'd be switching rooms the next day.
The room was so hazy and smoky it was awful! I woke up at 3 am feeling as I was being choked due to not being able to get a full breath. I almost slept in the bathtub just because that room had the least smoke stench. I eventually took a damp cloth and put it over my face in order to breathe a little but wasn't much help. 
I probably should mention that I have allergies and bronchial issues - so smoke bothers me tremendously. The smoke affected my entire next day as I was exhausted from no sleep and felt as though I still had smoke in my lungs. I also could smell the smoke on my clothes for the rest of my short stay in San Francisco.
They did switch us to another room that was non-smoking. And that was much better than the previous room. But on occasion you could still smell smoke. I think it was traveling through the vents, from an adjacent room or something. But it was very clearly cigarette smoke. 
The next day I went to speak with the manager and I was noticeably agitated because of my lack of sleep and shortness of breath. He did finally give me $40 credit for Fri and Sat. But my entire stay was thrown off after that horrible first night. I should not have to pay for that nights stay! 
Staff - for the most part were very friendly. They gave us suggestions of things to see and places to eat. We did try 2 of the restaurants and saw many of the sights. That was pleasant!
WiFi - is free and there are 2 computers in lobby available.
Location - is great. Right in Union Sq and very central. 
Rooms - are very small. Reminds me of rooms in Europe. The decor needs to be updated the carpets are dirty, the paint colors are interesting shades of green and yellow. It is all functional but definitely dated and falling apart. The plaster on the walls are very cracked. There are layers of paint that is peeling and cracking.
Bathrooms - were relatively clean but are a little cramped. The tub is positioned oddly and making an awkward L-shape floor space. The water pressure for a city hotel was weak. The water also varied in temperature while taking a shower.
Noise - AWFUL!!! Woken up at 7 am by protesters outside of Hotel Frank daily. The walls are quite thin as we could hear our neighbors clearly. You could also hear noise in the hallways - there was about an inch space at the bottom of the doorway into the room. We also had noise from the radiator!! It was like Chinese water torture! We could hear drips on and off all night.
Elevator - the elevator is extremely slow and small. 
This place, especially the rooms, has certainly seen better days. The staff is the only 4 star about this place - the beds were comfortable enough and the room was clean enough. When I travel I expect a clean, quiet, smoke-free, room and don't really need the extras - I am there only to sleep after all. But I would suggest to anyone to go elsewhere! Not worth the chance of getting the smoking room. On the flip side - if you are a smoker - this would be clearly up your alley!