Karsten was a very cool host. His apartment was everything he said he would be, it was clean and very sweet, he has thought of everything to make it the perfect little space to feel comfortable and at home in. He came to meet us on the night we arrived to give us keys and show us around the place, he then stayed a few extra minutes to point out some cool spots on the map and to tell us what we can expect from Berlin.
I would highly recommend Karsten's flat, it was super close to the subway, it was clean and well put together and in a very nice area.

Would definitely stay there again!