I've been this nice apartment with my family from 25th to 27th, July, 2017.
It was really clean and cosy apartment and the host, Paul was really kind and cared us during our staying here.
It was very accessible to go city central by Tram #2. And very quiet place at a night. Of course, safe enough to walk late.
I and my wife loved here very much and regretted to set staying this lovely city too short.
I am sure I will consider this apartment first when I'm in Vienna again. My point is 10 / 10. Strongly recommended.