Simon's AirBnb is excellent. It's centrally located between Kreuzburg and Neukölln. The area is full of great bars, cafes and boutiques. It also has several transport options just a few minutes walk away. The house was very clean, with everything we needed (including thoughtful gestures like fresh bread and milk).
Simon was very helpful and flexible with our check-in and check-out time, he even waited at the house for us when our flight was delayed.
I would strongly recommend staying here!