We had a great stay in Bea's apartment. There were 6 of us all together - 2 adults and 4 kids. The beds were all comfortable and there was enough space for everyone. The shower was great and we never ran out of hot water. The kitchen had everything we needed.
Bea was a great hostess, responded quickly to all our questions, and helped us out with various activities that we planned.
The apartment is located about a 10 minute walk from Prater - the amusement park. It was a good location for us with easy access to the Prater train station. It's also a quick train ride to/from the airport.
There were only 2 downsides to the apartment. First is that there is only 1 bathroom - which at times was problematic with 6 people staying in the apartment. We managed fine but having an extra toilet would have been helpful. The second issue was the street noise - since we were there in August, we had to keep all the windows open for air. Vienna is cool enough at night so that wasn't an issue but if your not used to city noise (cars, ambulance sirens, people talking in the street, etc...) it's a problem. I imagine if you're going in the winter and the windows are closed, it's probably fine.
Overall we had a great vacation and I would recommend staying at Bea's place!