I stayed at Silke's place, because I had a dance workshop at the same area. Silke was not at home, but I got the keys and the introduction from another person. Everything went well, apartment was well equipped and very clean.
I can highly recommend the apartment for someone who wants to stay in Friedrichshagen. If you want to feel the typical "Berlin athmosphere" Friedrichshagen is maybe not your place. There is a lake nearby and the surroundings are nice and clean:)