This is a lovely apartment. It is very large and was perfect for our family - 2 adults and 3 children, and could have accommodated more people comfortably. It is very clean and nicely but simply furnished. There are three very nice modern bathrooms with excellent showers and plenty of hot water. A nice kitchen/dining room too. The only thing I would change is to take away the piano in the sitting room and replace it with sofas so the room becomes more usable, but this didn't spoil our stay in any way.
The location is super, overlooking the Augarten Park in a quiet neighbourhood - it faces a local road but the apartment is so well insulated you hear no noise at all. Getting into central Vienna is very easy - there are buses outside the apartment but we walked 5 minutes to get the 31 tram to Schottenring (5-10 mins) where you can pick up the U Bahn or change trams to go round the Ringstrasse.
Gisella and Pia were incredibly helpful and welcoming which was really appreciated.