Alan & Kasia were on holiday when we were in Berlin but they were very helpful with advice etc before we arrived and arranged a smooth check-in.
The apartment is a good size and was in a good location for public transport, on a quiet street.
I don't think it is made clear from the photos that you enter the flat directly from the street (the outside is a shop front). The entire front wall is made of windows and the curtains do not fit properly so you are left feeling quite exposed.
The walls are also extremely thin, with an adjoining apartment just the other side of a door. We could hear the family next door so clearly it seemed like they were actually in the room with us.
Unfortunately, I would not stay here again.