Great position, dreadful staff
This hotel gets its star for its position - a few steps from Central Park West, very near the Natural History Museum and Subway station and an easy stroll to some excellent restaurants - try Sarabeths or Good Enough to Eat.
We've stayed at this hotel before (though never again), and were doubtful about the quality of service, but decided to give it another chance. Our welcome on arrival was curt and, I suppose, businesslike, but there was no line of waiting guests, and a little warmth might have been in order.
Our room was routine, with a fine view of aironditioning units and rooftop water storage. In the bathroom, the plug in the washbasin was completely ineffective, so we rang down and they promised to get it fixed. They failed to do so, so we had another try. The next morning at 7.30, while we were still in our dressing gowns, there was a thunderous knocking at the door. On opening it, we were confronted with an extremely large maintainence man who enquired with no courtesy at all what the problem was. 
We explained again that the purpose of plugs was to keep the water in the basin, and that was how we preferred things. To that his response was simply "Why?". I cannot easily say how intimidated we felt and how angry this made us. My wife is quicker witted than I am, and replied that we had paid a lot of money for the room and had every right to expect things to be in proper working order. Without asking, he pushed past us and into the bathroom to check for himself. On seeing that we hadn't actually been lying all along, he said in the same surly tones that he would deal with it after we had gone out. You will not be surprised that he did no such thing.
Indefensible behaviour. What rounded things off nicely was the discovery that in three weeks in the US, in hotels with a much higher star rating than the Excelsior, and also in simple New England Inns, the Excelsior was the only place that charged extra for internet access. Our experience suggests that, not withstanding the oleaginous promises made in their hotel guide folder about the high standards they maintain, they are in fact still in the dark ages.
Our strong recommendation would be to go to considerable lengths to avoid this hotel.