The flat is located right next to the Berlin Südkreuz Station, almost at the centre of the city. Of course you can take the S-Bahn (city train) to Potsdamer Platz (just one stop), but even better you can ride your bike along the tracks. There are a lot of bike lines and special bike tracks in Berlin and Südkreuz is the perfect place to start exploring the city on bike.
The apartment is simply equipped, but what do you need, when you're in Berlin? Despite the station nearby and the Stadtautobahn, it's remarkably quiet and we were able to sleep with the windows open. There is a industrial area right behind the small yard of the house, but that is also not noisy. The hosts were very friendly, very quick to respond. Definitely recommended!