I stayed for 5 nights in Wolfgang's flat and had a great experience. The apartment is very clean, modern, and well equipped, and I felt comfortable the entire time. It's a medium walking distance to the historic sights, but it's also very close by to a metro stop and tram stops, and it was very easy and convenient to get everywhere in the city. Wolfgang met me on arrival with some gifts in the apartment, and walked me through the city and apartment, and he was responsive throughout the stay. I would stay here again if I come back to Vienna and I recommend Wolfgang's place to others!