We had a very good time at Joanna's apartment. It is exactly the same as described here. It is very very close to sub-way train station and to the palace (10 mins by walk to the entrance of the palace).
Joanna was very nice and extremely helpful. She waited for us even thou' we were late by an hour. She did welcome us with grace. The apartment was very clean and tidy. I would highly recommend this place and would love to be here again when we visit Vienna the next time