I booked Karl´s appartement for my parents, they come to Vienna 2-3 times a year and this was the best airbnb appartement so far. Karl was very welcoming and well-prepared, he showed us where to find everything and recommended us cool places to go. The communication with him was easy, he answers right away, he´s a great host. The place was very clean and cozy, it´s exactly as described und there´s everything you need for a pleasant stay. The location is great, you have every type of public transport only 2 min. away, a shopping centre, supermarkets and nice places to go for a walk. I would recommend Karl´s appartement to everyone who comes to Vienna!