We had a great stay. Communication with David was very clear and prompt, we were welcomed at the excact moment we arrived from the airport. Everything was clean and ready and all the basics were present (kitchen necessities/towels/beds were made/soaps in the bathroom).
The appartement is well situated close to the Nashmarkt, Secession etc. There are some restaurants and shops in the area. And you are an easy tramride away (three stops with tram 1 or 62 around the corner) from Karlsplatz (U-Bahn connections) and the Oper.
David is a wonderful host, some information about the city and the neighbourhood was at hand and though we didn't need any further info, I am sure David would have been available ;-). Thanks a lot and we hope to be back !