Some of my family stayed at Bernd's place while visiting me. Although we chose the location for proximity to my apartment, I recommend it for any visit to Berlin. It's extremely central: walkable or an easy U-Bahn ride away from important landmarks in Mitte, and right in the middle of one of the most buzzing areas of Kreuzberg--tons of great international restaurants and shopping are just around the corner. Despite that, the apartment itself is quiet, spacious, and well-equipped. Bernd was a wonderful host, getting the apartment ready when I contacted him at the last minute and adding several thoughtful touches to welcome us.