Stayed here for 3 nights for my wifes birthday. We arrived early, about 9am (Sat) and check in wasn't til 3pm but hotel still let us in to our room, which was nice. Hotel is in a very nice location, less then 20 mins walk to Dam Square, round the corner from Van Gogh Museum and 10 mins walk to Leidseplein. If you are feeling lazy, the Tram stop is just round the corner, served by the 16 or 24 which both get you to Central Station in about 10 mins. You can buy a 48hr Tram pass for 12 Euros.
The rooms are very spacious and you get a more than you'd expect for what you pay. The bathroom is large and has complimentary toiletries too. Theres an iron, ironing board, hairdryer and kettle with tea bags provided in the room. Theres also a mini bar if you want something stronger...
The staff are very friendly and are always happy to help guide you with the easiest route to places. It was my wifes birthday on Sunday and they even left 2 (complimentary) chocolate mousse/desserts in the room for us - this was not at all expected and definitely made my wife happy.
Getting to the hotel from the airport - there is a shuttle service that drops you off and can take you back to the airport. It costs 27 Euros for the return ticket and is valid for a year. This was a lot cheaper than taking a cab.
We've already told our friends and family about NH Museum Quarter and when we come back to Amsterdam we will definitely be staying at this hotel.