Karl and Lisa's place is really nice to stay in for a couple of days! The ad has been absolutely accurate to what we have encountered( incl. commuting times, etc.)
The apartment was super clean,including linens,towels and cutlery provided. Karl checked on us on our day of arrival which was a really nice thing to do. We also got the impression that you can definitely contact him in any case of emergency. We don't really have a negative thing to say about the apartment.
The area also seems to be safe for young women walking around at night, so if you are looking for a nice place to stay whilst in Vienna, you should check out this place!