We stayed for 3 days in this nice apartment. It is exactly like it looks in the pictures, very comfortable and with a great well-equipped kitchen. Although it is not in Viena center is very well communicated and you can easily get anywhere you want by metro.
We didn't meet Kati, but her husband Bernd was a nice and helpful host as well.
If you're planning to visit Viena, I strongly recommend this apartment.