I stayed at Christian's place for a month this summer. The apartment is great, spacious, airy, and in a neighborhood full of excellent little cafes, local (read: cozy and friendly) bars, and Mauerpark's famous flea market. A great value. Christian was also very accommodating and flexible. I ended up taking a new job before I arrived and spent long hours locked in my room working. He never intruded and was there with suggestions whenever needed. You won't regret staying here.