First of all, Carsten Michael smokes in the flat, which is not announced in the ad.
I stayed at his place for two weeks and I have to say that I did not enjoy my stay there. If you plan to stay just over night or a weekend and do not plan to use the kitchen it will be ok, since the room is fairly clean and the location is perfect.
But If you look for a feelgood stay, I can´t recommend this place at all. I needed a place to work and eat, but I just stayed there for the nights in the end since I felt so uncomfortable and unwelcome. When I booked, there were no reviews so far. After a while. I saw that some people complained about cleanliness, but I thought it could not be too bad. When I arrived the bathroom was insanitary dirty with a trash bin that run over and a dirty toilet. The washing machine is mouldy so I would not recommend to use it, but there is a laundry shop just on the other side of the street. In the kitchen lay dirty cloths and everything you touch will leave some old fat on your fingers. In the fridge were mouldy vegetables and some slimy dirt. I had to clean every dish before I could use it and when I asked for a tea towel the careless answer was just no. The front door to the flat stood open for a whole night, what made me feel very uncomfortable. Carsten cleaned a bit after some days when an other guest arrived so I have the impression it is based on luck if you get a dirty or a clean experience. Since he did not care about this before I arrived I felt unwelcome and will definitely not recommend this place.