Before I checked Harald's place I read a comment that said that " it is the best Airbnb experience the ever had". I subscribe to that!
The place is clean, has a good location ( I used not only the buses, but also the metro (U6), tram( 9 I used the most).
It is also faced to a quiet and green garden. The bed, as you will find in the comments, gives you an amazing sleep, needed if you plan to visit the city. And even in the summer, the apartment is not hot at all.
If you need info don't hesitate to ask Harald!
10/10 would recommend it and hope to visit Vienna and stay there one more time.