The hosts were super cool and hospitable. We've had a great conversation together. Also, they gave us all information needed. If we had questions, we could ask them. The room was really cozy and the apartment was comfortable. It's in the centre of Berlin, what makes it easy to reach to subway and even on foot. As we came to Berlin for a concert, it was really cool to turn back by subway only, and not to use any additional vehicle. Moreover, near the apartment we found a lot of shops, restaurants, fast food, museums (The Wall, check point Charlie etc.).
All in all, your experience was great. If we ever come again in Berlin, we surely will stay there again.