We stayed a week in this nicely appointed flat in what was the former East Berlin and found it more than met our needs. The place was very clean and roomy, and quiet even though there are numerous restaurants and shops just out the front door. Both the tram and subway (U-Bahn) were just minutes away with great links to the rest of the city. A large grocery store was nearby and stocked everything we needed for our breakfasts and even a couple of suppers. There was also an organic food market a few blocks away. The WiFi worked perfectly.
John was a great host. He provided detailed information before we arrived on how to get to the flat from the main train station and what we could expect weather wise. And when he met us at the flat with a walnut cake, he had lots more information on restaurants, public transit and sights to see. He also gave us some freshly ground coffee and a variety of teas. There are many Berlin travel guides (both English and German) in the flat that cover almost any thing a visitor may want to see or experience. John helped us with our luggage (the flat is one floor up) both when we arrived and left. He even dropped off some laundry detergent after we said we needed to do some washing. He made sure we could contact him if we needed to and sent us an e-mail to see how we were doing and to arrange the return of keys and the damage deposit.
We tried a number of his restaurant recommendations and really enjoyed ourselves. The Greek restaurant he suggested had great food and, the evening we went there, even a Christening party with Greek music and dancing.
We would recommend John's flat to anyone who is planning a stay in Berlin and wants the freedom of their own place in a very interesting area of Berlin.
PS - I would like to get your mother's fruitcake recipe if she is prepared to share it!