Gerhard's room is exactly as described. Spacious, airy and with a nice lake view. The bathroom is clean and has a good shower.
Location wise, it seemed like a very safe area, even at night. And it's only a short bus or tram ride from Ostkreuz central station.
There are two decent 'markts' in the area (Aldi and another smaller). Gerhard himself is a friendly host, who gives good recommendations for things to do in Berlin and is welcoming with any requests you might have.
We would recommend anyone staying here.