I was in Amsterdam on a Business trip in July and stayed at the N.H Quarter. The hotel is very close to the Rjiks, Van Gogh Museums and some of the rooms overlook the canal. The canal facing rooms are bigger and better as compared to the non canal facing rooms, though the price is the same. Unfortunately, the hotel does not allow you to book the canal facing room in advance. The standard Wifi is complimentary but extremely slow ( you can take a faster wifi package for 10 Euros a day). Buffet breakfast is ~ 20 Euros (very expensive) and after having a look at the spread, not worth it.
The staff was helpful and friendly. The lift of the block I was staying in was out of service for 3 of the 6 days I was at the hotel. That seemed very unprofessional for a hotel of this stature and given the layout of the hotel, it is difficult to go to the upper floors if the lift does not function.