Cool place
Stayed here for six days for convention across the street at Moscone. I was aware that Ws were slightly hip but hadn't stayed at one.
Friendly check-in. Asked for a fridge and got one. Concierge helped direct me to a restaurant that fit my mood. Lobby bar is sleek and is absolutely the place to be on a night with a convention in town--use the other door if you don't want to walk through a noisy crowd.
Elevators and hallways are dark and mellow. I'm surprised to see some griping about the rooms. Mine was the basic "Wonderful" model and I thought it was cool, with a bench by the window that gave it a distinctive touch.
Had a few bumps along the way--such as one of the phones not working, and almost daily asking for cartidges for the coffee maker--but even though the place was packed, someone answered the help line right away and problem was fixed.
Free morning coffee in the bar. Last convention place I stayed at the only way to get coffee was restaurant or long line at lobby Starbucks. 
So, I enjoyed my stay; in looking at the prices, though, I don't think I could afford to stay with my own money. I guess that's how the premium places in San Fran are.