I highly recomend this place for a trip to Viena. It is a short bus, tram or subway ride to the city center, in a very nice residencial area with restaurants and nice local business. It felt very safe, and easy to reach all the places we wanted to visit. The house is very clean, warm and the bed very confortable.
Petra was travelling at the time, but we were welcomed by her friend wich was very nice and friendly. We also get to met her father, also very welcoming, and they made the check in and check out very easy.
I loved the details: the list with local tips for restaurants, supermarkets and local shops. I totally recommend Petra place.