We stayed for a week in June and couldn't have been more pleased with our choice. Our apartment on the 9th floor was extremely spacious, well appointed, with TVs everywhere and very effective aircon. The location is ideal in a smart sector of the city, right next to the Waldorf Astoria. We loved the neighbourhood around Lexington Avenue / 3rd Avenue with great restaurants and convenience stores and a relief from the tourist hell of Times Square and 8th Avenue (nearly booked a place over there - glad we didn't). Rockefeller Plaza and Grand Central are 10 mins walk away.
However, there is no such thing as quiet in NY. Due to the way the aircon units are fitted (removable in the winter), the windows are not sealed from street noise which seems to go on all night with garbage trucks, police, hotel laundry, etc. Earplugs are supplied by the hotel, but we were fine once we accepted how it would be.
Clearly, this is not a purpose built hotel - it is a conversion of a former old apartment block and as such, certain features are compromised; the lift is a little tight, as is the reception area and the breakfast bar is a squeeze in relation to the number of guests. However I would not let this put you off. The assistants in the breakfast bar are so polite and helpful, doing their utmost to run it efficiently through the 8 to 9am rush hour. Reception staff also extremely helpful and welcoming. We would have no hesitation in staying there again - missing New York already!