I travelled with my husband for a short visit to Vienna and we stayed at Ekaterina's appartment. The location is very good, is very close to Naschmarkt and to the U-bahn station. The appartment is large, clean and classy and our room was exactly as described. Ekaterina proved to be a wonderful guest, offering the privacy we needed, but in the same time offering us all the advice and support we needed. She offered us a great tour of the city centre and gave us the best advices concerning the places to see, the restaurants/cafes to go to, the shows to attend, others than the ones you can read in travel guides.
I truly recommend Ekaterina's appartment instead of any plain and impersonal hotel in Vienna.