Chongo and Zora are amazing, the place was very cozy, clean and stylish. Basically, the apartment is located in a very calm and nice neighborhood, it takes just around 10 minutes to get to the center and all the city attractions.
Very responsive and simply nice people, it was a pleasure to meet them! One thing I know for sure - my next trip to Berlin, I'll contact them again to see if it's possible to stay with them, cause this experience was very cool :)