Sascha is the best host you could possibly hope for. Even though he was on a vacation himself by the time when I was in Berlin, he managed to give me access to his apartment, answered all my questions and checked on me regularly to make sure everything is alright. The communication went really smooth and easy. Sascha was kind enough to let me stay a bit longer at his place, as I had a flight in the afternoon.
The room itself is very bright, clean and cozy. The apartment is situated in a quiet area. You can get easily to any place in Berlin using the S-Bahn or the U-Bahn (at least I used them most of the time) and the city enter isn't far. The neighborhood itself offers a lot - The botanical garden, Naturpark-Südgelände, Bierpinsel, shopping centers, etc.
If you are looking for a nice place to stay in Berlin, here it is.
Thank you, Sascha! Take care!