I stayed in Dörthe's apartment for a long weekend in Berlin to run the marathon. We were met by Dörthe when we arrived and were made to feel very welcome and at home in her place. It's spacious and clean with everything you would need for you stay.
It's located in a great neighbourhood with plenty of cafes, bars, restaurants and shops, and is not far from a lot of the main tourist attractions, either by foot or on the U-bahn, which has a station at the end of the street.
I would definitely recommend Dörthe's place and would stay there again.