Very good stay at Yellow Flower appartement. I spent almost two weeks and everything was pretty easy from arrival to departure. The appartement il fairly well located, just in front of the tram station that brings you to Kagran (mall and U-bahn station) in 5 minutes. If you prefer it is a 12 minutes walk from "Alte Donau" U-bahn station that leads you in the City Center in less than 10 minutes (even faster for the Prater). It is also a true 5-minute walk to Alte Donau that offer a really great promenade between water and nature, away from the big city life.
The communication was very good, the appartement as I expected it and very convenient for 2 people. Everything was clean and functional and the appartement is very comfortable. When the windows are closed the noise from the road is completely muffled. The only "bad" point was that the heating system was to hot and we were unable to fix it with the host so that I had to open the windows from time to time to stay below 26°C in the middle of autumn. The host was very reactive to my questions.
I would recommend it without hesitation.