The location has been mentioned by others as well, but it is just excellent. The area has plethora of restaurants and bars (famous Nemo is almost opposite the building). Tram stop is maybe 300 meters from the apartment, U-bahn around 400 meters.

The apartment was just like we expected from the photos. Nice, clean, well equipped. Comfortable beds in big bedrooms, the sitting and dining area, and small open plan kitchen. Worked well for us (two couples). We had a great time and would head back to Martina's apartment in a blink.