We had a wonderful time in Vienna, and Gudrun's place was perfect. Well appointed with interesting art, very spacious apartment (including a large bathroom), and even an espresso machine.
Gudrun is a responsive host, and when we had some issue with the key he was quick to respond and very helpful.
Also a good location, 5-7 minutes walk from the beautiful St Stephen's Cathedral, St Stephan's underground train station, and loads of great shopping and delightful cafes.