Markus himself is very prompt, communicative, and kind. Check-in was completely clear and easy. The flat is very clean, has everthing you need, and it's all private.
The location is about 15 mins to the edge of the Innere Stadt or 25 to Stephansplatz. There are not many shops, restaurants, or markets in the immediate vicinity, BUT, if you plan to be out exploring beautiful Vienna and not go back and forth it's fine. Personally, think the price is high for the location and size.