Stayed for 3 great nights at the St. Regis. Room was well appointed with quality furnishings and very comfortable. The large bathroom was spotlessly clean and the layout with the opening by the bath to the bedroom worked well for a couple; and could be closed if needed if travelling with friends.
There was a conference going on in SF whilst we were here and the hotel was very busy. The bar itself was full every night and did make the lobby a bit noisy; but didn't have any impact on service (check-in was quick; valet typically retrieved car in 5-10 mins). Would definitely visit again.