I had the pleasure of staying at Christiane's place for an entire week on March. The place has many advantages - a warm cozy living room, cool kitchen (which is fully equipped), and a small but very handy (and quiet) balcony.
You can find anything within 100 meters distance from the apartment, whether it is a supermarket, pharmacy, and some restaurants which are actually open until the small hours. Communicating with Christiane was easy and went without any problems. In addition, although I ended up landing a bit earlier than I expected, the apartment was ready and I got the keys plus full instructions on the electric utilities. Bottom line - the best place in Wilmersdorf that airbnb has to offer, and a truly kind host.