We stayed with Eric and Gini for 3 nights and had a fantastic stay. They were very gracious and flexible hosts who gave us a warm welcome and helped us get our bearings with the area. The flat itself is newly renovated and has everything you could wish for. (Including heated floors which were very welcome as it was minus 6 degrees when we arrived!) The flat is situated in Friedrichschain, which is the newly gentrified area of what was East Berlin, and is a stone's throw away from Warschauer str, which is the Main Street, and only a 10 minute walk to the East Side Gallery and the nearest train station. I would definitely recommend staying with Eric and Gini and hope to visit Berlin again soon!