Very nice and cozy roof apartment. Karl is very hospitable and is always in contact, tries to help with all possible inconveniences (how to get to apartment, about public transport in Vienna, etc). You can check-in on your own, so you don't have to wait for the host. For the first time it wasn't easy for us, frankly speaking, but then the system seems to be the most comfortable for both (host and guests). The apartment looks exactly like in the photos, it's quite large. A very good and clean bathroom. A great option to stay at in Vienna.