Christina was very nice and welcoming, even if we arrived later than scheduled. She took the time to show us all the devices in the apartment, which is nice and fully equiped. It is located in a quiet area, near a subway station, shops and restaurants. The walk to the city center is about 20 min long and really nice.
Overall, we had a great experience in Vienna and in Christina's apartment. I wouldn't hesitate to come back to hers if I travel to Vienna in the future.