Cristina and Alexander's apartment is lovely, just as shown in the photos--spacious, bright, comfortable, modern, and very clean. The location is directly overlooking Hackescher Markt S-Bahn station and so extremely convenient to transport (trams also stop right by the station, and buses just a block or so away), yet as the bedrooms face away from the train station and the apartment is on the top floor, it is quiet at night. It is also convenient to shops and restaurants, and there is a market in the piazza twice a week. We did not meet Cristina or Alexander but their friend met us with the key and Alexander did stop in to replace the battery in a smoke detector that began to beep. They also left us tickets for a concert that Alexander's band was giving, but unfortunately we were at the opera that night and could not go. (Maybe next time!) Strongly recommended!