In October 2006, I booked into City Hotel, Amsterdam (above the Old Bell Pub). I had stayed there 5 years ago, and found it basic, but clean. I booked over the internet which featured photos of large, clean rooms. Upon arrival we were taken to a room in another building. The stairs were steep and winding, the walls and carpets stained and filthy, and the air stank of mould. The room was as bad, plus stained sheets and a blood-stained mattress.
I returned to the desk, explained that this was not the room I had booked, and that it was unacceptable. I asked for a full refund. The woman who had taken our money was gone, and the part-time employee said he didn't have the authority to refund our money, and to return in the morning. We couldn't stay that night, as my partner has health issues that made it unwise to expose her to the apparent mould and bacteria present in the room. In the morning we returned, and after very difficult negotiations, only got back some of my money, minus the previous night and "commissions" for the remaining 5 nights. They were very rude, and ruined our stay in Amsterdam. Upon return, I discovered reviews of this hotel, with similar experiences, plus accounts of robbery. My guess is that this hotel has changed hands, so even if you had a good experience before, it is no longer a safe, clean place to stay.