My husband and I recently stayed 7 nights in Karsten's apartment where we were warmly welcomed by Karsten and shown how everything worked. Immediately it felt like home away from home. It is even better than the photos and is immaculate. We loved this area of Berlin with the restaurants, markets and family living. It is 3 mins to the tram and in four stops you arrive at Alexander Platz.
Karsten is a great host, replying promptly to emails and answering all queries. I highly recommend this apt.