Stayed on business travel in July '12. Attended a workshop at the hotel.
Rate was $369/night which is high for the area. Room was clean and basic - like dressed up Ikea, which I've come to expect from W Hotels worldwide. The gym was small but functional. Get used to club/house music whenever you leave your room - it's in the lobby, in the elevators and eventually in your mind whether you want it or not.
Bar - I enjoyed the 2nd level bar where we had a reception, although a larger selection of draft beers would be nice.
The conference room wifi was terrible, just terrible. They had a wifi port limit less than the number of attendees, even though the sponsor asked for the "premium" package. Throughout out the day the attendees were getting rejected when they tried to connect. Totally unacceptable - this is SF after all where connectivity is offered nearly everywhere. In today's day and age, you need at least 2 wifi ports per attendee.
I do 50-60 nights of business travel annually and there are a few things I expect from a business class hotel (or one charging such a high rate):
1. Quality wifi - mixed bag. The room wifi was great, but as I mentioned the conference room wifi was terrible.
2. Coffee and coffee maker. The room had no coffee or coffee maker, choosing instead to stock the room with a ridiculous amount of alcohol.
3. Power. I'm always traveling with 3-10 devices that need to be powered every night. I hate having to search for outlets, unplug a lamp or charge in the bathroom. The workspace at the W is excellent with a double strip of outlets. Whoever designed this deserves a reward.
4. Iron and Ironing board - both available in the room.
5. Quality TV - flat panel inset above the workspace, kind of a tough viewing angle.
I would recommend you check out some neighboring hotels which I've stayed at for lower rates and are as nice as the W: Grand Hyatt, Hilton, Marriott
hotel reviews