This was an absolutely wonderful stay in Berlin for my family. I came for the Berlin marathon, and this was the perfect location. The apartment itself is on a very quiet street and I had absolutely no issues walking around at night, even at 1 am in the morning. It's 5 minutes from the nearest subway stop (U5), which takes you directly to the starting line of the marathon, or elsewhere in the city very easily. It's also a 5 minute walk to the marathon course itself if you have spectators with you. There are also lots of delicious restaurants nearby within walking distance, and we never had an issue finding a place to eat.
Simone is one of the best airbnb hosts I've ever met! She is friendly and kind, and provided me very detailed information all about transportation, the apartment, and the neighborhood. The apartment itself has all the amenities you need, towels, toiletries, pots/pans, etc and there are grocery stores within walking distance. We had two adults in our group total, but there was space for more. I would definitely hope to stay here again when I come back to Berlin.