My Wife and I stayed here in April 2014. The Hotel is conveniently located almost right outside the railway station but you should not let this put you off as you do not hear anything once inside. The room was spacious for Dutch Hotels and the air conditioning\heating was controllable by us so we could have the room just as we wanted it. It was a nice touch that this wasn't adjusted by the house staff when cleaning the room.
The restaurant choice was a bit limited in the evening and this may be a problem if you were to stay for a longer period and eat in every night. What was there was incredibly well cooked and my wife commented that it was probably the best meal she had eaten in many years.
I can say without a doubt that the quality of the room, the service on the bar and the service in the restaurant was amongst the best I have received in any of the hotels I have stayed at throughout Europe.
We didn't use the Spa so I have not rated it you should not take this as a negative we just didn't have the time to use it.
When we return to Amsterdam (which we will) this will be our first choice of Hotel.