I had the chance to spend 28 nights with my wife and daughter in Jan's & Martina's flat, and I can say it was worth it. Jan is very responsive and solved all my requests as quick as possible.
The shower had a problem and I texted Jan, who were at my door the next morning for fixing the shower himself in just a couple minutes.
Only negative point about the whole period I spent in the flat was that when we got there, the whole flat was a bit dusty probably for beeing empty for a few time. Apart from that, everything else was good, and we enjoyed our stay.
I recommend it!