I stayed with Cornelia with a friend. The apartment itself was nice. Clean, big, and close to the efficient Vienna transit system. The one complaint about the place itself was the size of the towels. She only gave us hand towels.
Despite the decent apartment and location, my friend and I had a very negative experience with Cornelia. Cornelia did not seem like she wanted to be hosting us. She was impatient with us when we were giving us our arrival time (which is always subject to change when traveling).
I won't mention all the subtle negative interactions for the sake of brevity. What made me and my friend decide to cancel the remainder of our reservation was a negative encounter with Cornelia and my friend. The day after my friend and I arrived, while my friend was in the bathroom, Cornelia knocked on the door multiple times. My friend could not answer, but when she came out of the bathroom, she noticed that the door had been opened. (Cornelia had entered the room without permission and we have reason to believe that she did this more than once). Cornelia then knocked again much later. My friend, while she was still in a large blanket (because of the small towels), opened the door to see what was up. Cornelia entered without invitation and complained that we had broken the window because we opened it wrong. She said 'this is very very bad' over and over again. (This was not the case as my friend closed and reopened the window properly right after she left.) Cornelia claimed that she had seen from the street that the window was broken, which would have been very difficult to see from the street as it is a penthouse. Overall, we found her to be very controlling and rude as a host. We felt uncomfortable staying there and decided to cancel our reservation early, honestly because a host should never ever confront guests like that, not when she is naked with a blanket covering her person and in that tone. I felt more safe and comfortable in a hostel than I did staying with Cornelia. My friend and I only briefly glanced at the reviews before booking. If we had read them extensively, we would have seen the equally negative reviews. Please feel free to stay here as it really is nice, but you have been warned.