This hotel is located in a suprisingly quiet and nice part of Midtown (41st and Madison) near the NY public library but within just a few blocks of all of the action. Grand Central Station is less than 5 blocks away. My sister and I stayed for a girls' weekend and did not hear any traffic or other hotel guests even on Saturday night. The best part for us was that this was not a touristy hotel in the slightest. No tour groups to be found. The hotel is extremely classy with a large reading room that has a complimentary pastries, juice, tea and coffee available for hotel guests 24 hrs. a day and has a complimentary wine and cheese happy hour. The included continental breakfast was quite nice, with bagels, yogurt, fruit, pastries, etc. Free DVD rentals are available from the hotel's DVD library (ranging from Snow White to Butch Cassidy).
Everything was very tastefully decorated, with classy decor that was interesting but neither gaudily traditional nor extremely trendy. As such, I would recommend this hotel for both younger and older patrons. We stayed in a single room because all other rooms were booked. It was a typical size for New York (smallish) but comfortable, with a nice double bed and clean bathroom with full bathtub.
As far as we could tell, the service was good, though we did not have much of an encounter with the hotel staff beyond checking in and out. If you're looking for a party hotel, try the Tribeca Grand. If you're looking for a design hotel, the Gramercy Park Hotel might be better. But if you just want a nice, quiet, comfortable hotel, I would highly recommend the Library.