The apartment is in a perfect central location, three minutes walk from Karlsplatz U-Bahn station, which connects directly to Wien Hauptbahnhof and easily to Wien Mitte station.
Despite being central, during our April stay the area was calm and quiet, particularly at night.
This is a perfect location to take in all the Altstadt/Innere sights of Vienna on foot.
The apartment is well equipped for self-catering and relaxation. It is spacious, clean and tasteful.
Jeroen was a good host. His communications were great, he is fluent in English for the non-German speakers, and he was accommodating with check-in/out flexibility.
We had plenty of information to plan our short stay so no need to hassle him for much info, but he did give us some useful tips on local eateries for cheap and authentic Austrian food literally a minute in either direction from the apartment. Check out Braunerhof Cafe or Reinthaler Gasthaus. Cafe Hawleka (basic tasty Austrian gulaschsuppe and bratwurst available till late), & Reinthaler Beisl are equally close.
For the money and the location, this is probably the joint best AirBnB I've had, out of about 5 trips.