We stayed as a family of 4 - 2 parents with 2 sons aged 20 and 17. The parents had a large room with large bathroom (#41) on the fourth floor overlooking Jülicher Street. This street is busy in the morning - lots of delivery trucks, people talking, crashing and banging. After the first night, we got used to it, but given it was hot when we were there, we had the windows open at all times. The bathroom was large and well equipt. It was sparcely but tastefully furnished leaving lots of room for us and our stuff, as well as our sons to visit from their room. They had a very small room with 2 twin beds and very tight bathroom - you could barely close the shower door as it swung in. Luckily our boys are very slim! The window looked over the back of the hotel - not as attractive, but quieter.
The only complaint we had was that the wifi was really only effective if you sat in the hallway between the bedroom area and the bathroom (still within the room). Once you moved to the bed or desk, it would cut out and you'd have to reconnect in the hallway. We must have signed in about 20-40 times per day with our room number, name and date of check-out.
This hotel also has a restaurant which we ate at the first night. It was good, but there are so many choices in the neighbourhood as well as closer to the city centre that we only ate here once in our 6 days in Cologne.
Overall, a lovely place.