I've stayed here twice,both times for conferences. I think they do an excellent job,the conference rooms are spacious and well equipped and the meeting areas great and very well catered for -great coffee machines!
The catering for the conferences is always fantastic! and the staff are extremely helpful and professional .
Rooms are spacious but spare with big beds and really comfortable bed linen, tea and coffee making facilities and a fridge and a really nice simple bathroom-everything is absolutely spotless.
The only problem is it's quite close to the airport so you do get a sound of planes from time to time and they have been doing building works-you are offered complimentary ear plugs -I didn't even notice this time.
It's also a little far out of the centre, but you are right next to the Amstel metro stop which also has a great little shopping plaza -again spotlessly clean! And numerous tram lines-you can get out to Schiphol in 20 minutes for 4€.
The restaurant downstairs is ok -it's a bit dark and not very intimate and I think the food, while good,is actually quite expensive for what it is, there is a very nice bar/restaurant five minutes walk away called Dauphine's which I think is much better.
The Circle Bar upstairs on the other hand, is really nice.
As I said, I've been there for conferences and so there is an advantage to staying in the hotel, if I was going to explore Amsterdam , I would probably stay closer to the city -but I really can't fault it, extremely well equipped, great staff and you can rent bikes as well. Would totally recommend, it's perhaps more geared to business than pleasure, but I will definitely stay there again.