Great Location, Good Facilities, But Somewhat Lacking in San Francisco Charm
We arrived to discover that our reservation for an upper floor view room with a king bed had somehow morphed into a queen room on a lower floor. Fortunately, the desk clerk rectified the issue without complaint. 
Our reassigned room was on the 21st floor, and although not the "odd" numbered room above Cyril Magnin St. with the best views, it had a decent view nonetheless.
My general impression of the Parc 55 is that it is a good convention hotel, but lacks warmth. The lobby area is sterile and often loud. The hotel restaurants are adequate, but nothing to write home about. The rooms are what one would expect for a hotel of this type - clean, in good repair, with comfortable beds, but nothing to make them stand out. There are probably better values, but we had no complaints because this was a relatively last minute booking and most of the boutique hotels I would have preferred were already sold out - it was a World Series weekend, also the weekend before Halloween.
Some of the previous reviews have complained about the street noise and the exhorbitant parking charges. However, there was no need for earplugs in our upper floor room, and the valet freely volunteered the location of a parking garage only one short block away that charged one-half the daily rate of the hotel garage.
In short, we would return, but not as our first choice.