I stayed in Jons appartment two weeks in September 2012 and had a truly great time. Jon was a good host, the appartment was nice and tidy and tre rooftop garden is wonderful on sunny days. The location of the appartment is very convenient. Most of Prenzlauerberg and Mitte are within walking distance and the Rosenthaler Platz U-bahn is literally right outside the door. If you are looking for a centrally located appartment in Berlin then look no further