Katharina is the nicest host I've ever met. She is really friendly and puts a lot of care into making you feel welcome. She replies to messages right away, and with a lovely tone, and is always approachable on the phone.
Her apartment is very beautiful and cozy. The bed is so comfortable. And its location near the central train station makes it very convenient. I only stayed there for one night, but if I come back to Vienna, I'll surely try to book her place again.