The location really is superb! The apartment is in a secure block and was spacious and very clean.
While we were there, Vienna and the rest of Europe were experiencing a heatwave with 32°C every day. We did struggle a bit without air conditioning. Peter did his best to try to relieve the issue providing two fans. Peter was exceptionally good to us as many others have commented.
However if lack of air conditioning is an issue for you avoid this flat, at the hottest time of the year. If not, for the heat, our stay was excellent.