The host was very friendly and accomidating, and willing to answer questions and help as needed. The location was nice and quiet, and it was in a good neighborhood.
The apartment was as described: A very small guest house. Although small, it has just about everything you might need: It's similar to living in a very well equipped RV. The bed (as other reviews have noted) is sleeper sofa, and although the host does offer wi-fi, it is not very reliable.
The apartment is a short walk to the nearest S-Bahn station, from where it is about a 40-minute train ride to the city (depending on where, specifically, you are going). Basically, you are in the extreme south-east corner of the city.
All told, it's a good place to stay. The price is right, you have excellent hosts, and it's a quiet and comfortable place to sleep.