I stayed at the Hotel Nikko for business. The location is central and convenient to transportation (it's near Union Square - which other than being central doesn't have too many positives. It isn't the prettiest area.
That said, the hotel was quite comfortable. I arrived early (around noon) and the staff was able to accommodate me with an early check-in. The room was nicely appointed: very comfortable bed, good electronics and the bathroom was quite nice (with a separate shower and tub).
I didn't take advantage of any of the other hotel features (room service, gym, etc..) so can't vouch for those, but I was quite happy with the room.