I spent a month at Marfisa's place. It was a very nice apartment - clean, well located (quiet courtyard in a lovely street, close to U-Bahn and trams), equipped with all the amenities and excellent wi-fi. Marfisa is a very considerate host, responsive and cheerful. Check-in and check-out were perfect. I recommend Marfisa's place to anyone staying in Berlin for holidays or professional reasons.