Gabi's apartment listing is accurate. The apartment is very conveniently located and all the major tourist attractions are either within walking distance or connected through metro/bus/tram, whose stops are very close to the place.
The apartment is very clean and comfortable to live in and has every possible thing that you might need to have an amazing stay.
Gabi is an amazing host and helped answer any questions we had. There were no problems at all during check-in and check-out. Gabi herself met us at the door when we arrived and gave us a tour of the apartment.
I recommend Gabi's apartment to everyone and I hope to stay here again when I come back to Vienna next year.