Karsten was an excellent host who took the time to meet us personally and recommend local places, his map & advice was very handy. We found the flat clean & spacious, a really cool design, with extras like tea, coffee and foods provided. It is close to the metro and trams, and near a nice park. We found it a good base to explore Berlin. The only thing we would point out is that it is on the ground floor and at the front of the building, it looks like it was originally a shop, now converted into a studio flat. This means when people walk past the windows talking you can hear it very clearly from the flat. It feels like they are in the same room. This made it hard to sleep nights when it was busy outside, there was also people just hanging around outside the apartment block next door, talking all the time. Overall we still enjoyed our stay.