Martina and Charlotte's place was great for my family of four. The apartment is stylishly decorated and was very clean when we arrived. There are many good bars and restaurants in the area, and the apartment is just a short walk from the Kottbusser Tor U-bahn stop.
Martina met us at check-in. She was very kind and gave us lots of great advice for local places to eat, and getting around Berlin. She was always prompt to respond to her emails.