We stayed at the Hotel Calm when we went to see Placebo in concert at the Zenith Arena and wanted somewhere you could walk to from the arena. The Hotel was very central. We never needed taxis, we could walk everywhere we wanted to go to.
The room and bathroom were very clean, but the bedroom sometimes felt very hot at night. Breakfast was available at a supplement but there were so many places nearby that you didn't need breakfast from the hotel. Can't comment on the breakfast as we didn't get it at the hotel.
Staff were very friendly and helpful. I suffer from vertigo and we only had one pillow each in the room, but they gave us more when we asked without any fuss.
It's an old building so there were some winding staircases, although it does have one lift as well. Our room was quiet, but I see some reviews here that it was noisy. I suppose it depends in which room you stay in, ours was away from the road. So ask if you can book a quiet room.
Some rooms do seem larger than others, as there was a floorplan on the back of our door. Ours was medium sized and didn't feel cramped. Only one side of the bed had a bedside table though which was slightly awkward.More