We stayed in Mark&Anna's place for a month and it was really smooth. They were overseas at the time but it didnt feel like it at all. The flat is exactly what it seems in the pictures, cozy, urban, stylish, tidy and neat. It is so central, and close to transportation you can go east or west without any hussle.
Mark&Anna even prepared a little booklet for us about, how to go and where to go that was very cute and helpful. They were always a message away even considering the huge time difference.
I would say dont even think about twice, this flat and the owners are what you are looking for in airbnb.