I admit I was skeptical booking the W for a sleepover for my daughter's birthday (yes, she's spoiled I know!). My main concern was noise hosting four girls. I was also worried that having been opened for a while the W migt have lost some of it's luster. I was wrong.
Not only was noise not a problem (the walls are amazingly well insulated for sound), the hotel was still modern, impecably clean and well-run.
Service was excellent. Every staff member was kind and polite and extremely helpful: on the phone when booking, at the front desk, at the pool (which was warm and very fun), at room service. While modern, the W is not pretentious. The beds are comfortable. The linens fit and don't exfoliate you as some overstarched sheets do at many hotels, the rooms are a comfortable size. All in all excellent. We live in town so location was not the point of this stay but for visitors, the location is excellent as well.
Loved it.

During our recent stay, we upgraded to one of their suites. They have several types of suites and ours was called Fantastic Suites. There was plenty of room for both my husband and I. The Fantastic Suite had a living room, bed room, and 2 full bathrooms. So there was no need to fight for the bathroom between the both of us!

The W Hotels all over provide Bliss toiletry products and this location was no different. I'm a hugex2 fan of Bliss products and looked forward to using the hotel toiletry products (usually I bring my own toiletries when not staying at a W hotel). The water pressure from the shower wasn't as strong as we'd like. And in both of the bathrooms, the toilet roll holder that was mounted onto the wall was placed in an awkward position! Basically we had to stretch our hands to reach out to grab and pull the toilet roll. It wasn't in the most strategic or ergonomic position :)

The W San Francisco is what you would expect from the brand's concept and theme-- hip, young, contemporary. The elevators are dim with funky music playing. The rooms are far from classic and traditional but instead abstract and contemporary. Service was wonderful and each time we requested something from housekeeping, customer service gave us a follow-up call to make sure we received our requested items. Their bar/lounge was hopping during the weekend.

The location is fantastic and walking distance to anywhere in downtown. On the same street are other Starwood properties as well (Westin and St Regis), and the W is the hippest (or I should say, the least classic) of these other Starwood sister properties. Outside the hotel is the MUNI bus #30 that will take you to Chinatown although it is really a short walk there anyway. The Powell BART station is also just a short walk away (perfect for traveling to and from SFO). The W is also right next to SF MOMA.

W has two entrances. One of them takes you straight to the bar/lounge area. The lobby and check-in is just right of the lounge.

We stayed at the W for two nights before going to Napa. We received excellent service from the time we checked in to the time we checked out. We had an awesome view overlooking the park. It's a beautiful hotel with great amenities and excellent staff who provide wonderful customer service.

Stayed 4 nights at the W in San Francisco for a conference (Moscone Convention center). Arrived early and received good service at check-in. Room was spacious, clean and nicely appointed. Room amenities were a bit spartan for a hotel in this price class (needs a lamp at the desk, clock at night desk, and extra table for dinner trays). Bathroom is not up to class, while clean and functional, I expect more for my room rate (please put a soap dish in the shower and a hook or bar for the towel). Room service is excellent (quick and food is very good). Overall service was very good, always courteous and quick to respond. Had some problems with WIFI, which was resolved quickly. Like the 'house-keeping as needed' option.
So, in summary, moderate price to value ratio, great location for business meetings, very good service. Would choose this hotel again. but only for a conference at Moscone.