Room 55 (first floor - back of the building). Stayed on a Tuesday night. Single room with small double bed, coffee & tea, mini fridge, TV, and en-suite with shower. It was a nice clean room and a comfortable bed. It had a hook in the bathroom, and as there was no wardrobe it could do with a hook somewhere in the room for a coat. You get a nice stay, but skylight is the only window and as such this is a room for a quick stay over rather than a longer break. Hotel Oscar is located on the edge of the busy part of Amsterdam centre and easy to walk to from Amsterdam Centraal Station. Everything is within easy reach including the Metro.
On checking reviews the day before my trip they were inundated with comments about the nightclub situated behind Hotel Oscar. If you are at the back of the building you will hear this every night of the week. However, for me there was no room shaking, it was barely noticeable, more like a tap dripping. If you are a light sleeper and you focus on small noises I can see this may be annoying. When booking if you are concerned this may affect you book rooms at the front of the hotel. They do not offer upgrades.
Couple of Amsterdam Coffee Shops in this area for those that like that, absolutely no smoking allowed in this hotel.