The apartment was as advertised (even looked better in real life). The 5 of us were comfortable there (one had to sleep on the extendable couch, but that was not a problem). Location is great, very close to the strict city center (only 3 U-bahn stations) and to the Schoenbrunn park/castle/zoo (also 3 U-bahn stations in the opposite direction). The U-bahn station is 5 minutes walk from the appartment. It is also quite easy to find free parking during weekends (not possible during weekdays, but that's Vienna).

The host was really friendly and helpful (even helped with the bags).
All in all, a very positive experience and would stay there again.