We had a lovely stay at Kati and Bernd's apartment. The location is excellent - a short walk to the U Bahn & tram or a 10/15 minute walk to the city. The red route Big Bus Tour stops nearby as well. The apartment is very clean and has good amenities, photos are accurate. Check in was very simple with Kati booking us a taxi from the airport and Bernd meeting us at the door and, even though we arrived late, he spent some time answering our questions and gave us some useful, local information. Would highly recommend and definitely return if we found ourselves in Vienna again!