The apartment is very nice and cosy, well located, and clean. The description of the place is accurate and all facilities were to hand that we needed.
The apartment was easy to find and well located, only a minute walk from the nearest underground station and couple of minutes from the tram. The next street along -where the station is- has many shops, supermarkets and restaurants. We never felt the area we we're in or nearby was unsafe. The underground is on the U1 line which leads right in to the centre and line transfers are available to anywhere else in the city, we never had to travel more than 30 minutes away to see a landmark.
The apartment is well furnished and private. There is a large window out on to the street which lets in lots of light and blocked out the little street noise there was from getting in to the apartment. We were also mostly unaware of any neighbors being around, hearing a bit of chatter in the stairwell once but otherwise we didn't see or hear anyone. The furniture was comfy and after returning exhausted from a long day of walking, we were able to relax well enough to get up and go again the next day.
Walter and Heni were great hosts, sending us a load of information about the area before we arrived and making sure we were setup to get in to the flat without them and made sure we knew how to get there from the airport. Communication was great throughout, from booking to leaving. They have been very kind to us during our stay and it is obvious that they take pride in hosting. I would recommend them and the apartment to any friends wishing to visit Vienna and would happily return to them on my next trip.