Brusque service, tiny rooms, great location
Bottom line: Don't kid yourself that the high price tag buys you anything but a good location.
We had the misfortune to stay in this hotel during our last trip to New York City (which was wonderful besides the hotel, check out my New York City list to see all that we did). The first thing that put me off was when we pulled up at the curb there was no bellman to greet us or take our luggage, meaning that we had to carry our own luggage up a set of stairs and through a revolving door -- definitely a feat of physical agility that I would not recommend to anyone with mobility issues. Once we mounted the stairs with our luggage, we approached the check-in desk, where we were not greeted with anything beyond basic human civility -- "Name? Credit Card? Here's your room key." No one offered to help us with our luggage on our way to the room. 
We stayed in a tiny, undecorated room directly across from the elevators, which ensured that every morning we were awakened by a large group of people who had gathered in the chairs outside to await the rest of their party. Our room technically had a view of the street, which I suppose was better than having a view of someone else's room. The bed linens were rough and the comforter was lumpy. There were literally no decorations in the room - not even a single generic art print on the wall. The bathroom was very small, with precious little space to put any toiletries. For the high price we paid for the premium of staying at this hotel, I really would have expected better. Understandably they probably can't do anything about the size of the rooms, but surely they could put more effort into improving the quality of the materials within and the decor? 
On our last day, we stood in line to have our bags stored while we spent the rest of the day out and about (our flight didn't leave until later that evening). Like other reviewers have stated, the baggage attendant blatantly asked me for a tip, saying that he wouldn't be there later when I picked the bags up. He said it in such a way that I was actually worried my bags would get "misplaced" if I didn't tip him before he took them off to the back room. That is just bad customer service, and completely inexcusable for a four star hotel.
The best thing about this hotel was the excellent location. It was only a handful of blocks away from Grand Central Station, the Empire State Building, and the UN Building. We had a longer (but still manageable) walk to Times Square, Broadway, and Central Park. If you are in New York to do shopping, 5th Avenue is very nearby, and there is also lots of shopping on neighboring Madison Avenue. We had no problem catching taxis outside the hotel for trips farther out.