Good for Broadway lovers
If you're a tourist, you're gonna love this place.  If you're here for business or want a discreet vacation, this is not it.  Location is right in Times Square which is either a positive or negative depending on your point of view.  Lots of people in Times Square means getting in and out efficiently not always easy.  Elevators from ground floor take you to lobby, then another set take you to the rooms.  This set-up is always somewhat annoying, esp late at night when you're exhausted.  The lobby was overflowing with people on check-in without enough seats to accomodate them, which degraded the "hip" feel of a W initially (minor detail).
Rooms are W modern.  Stayed in standard room which was a bit more spacious than expected for Manhattan, though my expectations were low (all standard rooms in NYC are very small).  If you're spending that much time in your room on vacation in Manhattan, you're either on your honeymoon or you need a psychiatrist.  There is always road and city noise of some kind pretty much anywhere desirable in Manhattan, so expect a certain background buzz especially in Times Square.  
Overall, good but not great.  I prefer W Union Square for a more intimate feel.  Though if you're booking in Times Square, you pretty much already know what you're in for.