The apartment is just great and exactly as described. Lots of space, good condition, all facilities there, authentic and stylish. Even the front door has some Gustav Klimt-style golden bling!
Perfect location for sightseeing. Opera House/Hofburg Palace are a quick 10 minute walk. Tram lines and underground go everywhere and are close. The city is flat, so if you fancy walking, it is perfectly possible in an hour to get to the Schonbrunn Palace even at a kids walking pace. The train stations are also close if going further afield.
It was nice to meet our host Mirella. She was very friendly. Answered all communications instantly, arranged a transfer for us to the airport and when we requested checking in a bit earlier than strictly allowed to leave our bags, she let us. There is a file in the apartment that she has put together listing good places to eat and other info which was also useful.