Karl is a very kind and friendly host. He was extremely helpful and made sure that we have a comfortable stay. The apartment was spacious, clean, warm, bright and charming. There was coffee and tea and Karl had breakfast for us in the fridge!
The location is very good, just 2 minutes walk from the train/metro station and it was very easy to go around with public transportation. A train also goes to the airport. Moreover, there was a large supermarket and also a shopping center next to the station (that is only 2 minutes from the house) and there were a lot places to eat.
It is a great value for money and we would definitely stay there if we visited Vienna again.