New York has a different normal
Debated the rating on this one; 3 vs 4, but frankly, guest rooms are the most important aspect of the stay. This one let me down a bit. First, the Affinia Manhattan is clean, has an attractive lobby, and an excellent, if underpopulated, staff. The room was very small, about 20% larger than the king bed it contained, with a window AC unit. This is common in NYC, but the rooms are good for sleeping only. The bed was very comfortable, and the sheets were medium quality, the towels a bit better.
The Affinia made the most of it. Well decorated, clean and bright, it avoided the claustrophobic feeling some rooms have. The tub/shower is small, the sink has very little space for toiletries, and even the toilet bowl was a bit smaller than usual. If this doesn't bother you, then the rest of the hotel is quite nice. 
The lobby is spacious, well decorated and large. The staff is top notch, though it seemed a bit too small for the demands placed on it the days I was there. There is a fitness center and a restaurant that offers a 20% discount to guests. This being Manhattan, though, finding a place to eat is a snap in all price ranges.
Hard to beat the location. Penn Station and Madison Square Garden are right there as is an additional subway station. I had meetings in Long Island City and near Union Square at 8 and 10am the same day and had no problem making them easily. Also, there is a large meeting room for conferences, but that seemed to be the extent of meeting facilities. Newark airport (EWR) is a train ride away, LaGuardia (LGA) about a $35 cab fare, 30-40 minutes. JFK is a flat rate, though I don't recall what that is.
On the web site, there is an option to "customize your stay" with the Affinia Concierge. There, the hotel offers a number of options that can adapt to varying preferences. It's a nice touch.