We had a long weekend in Theresa's flat and really enjoyed it. The flat is big and bright, pictures really don't do it justice (as it is in fact much nicer :) )! I also loved its central location, which is in the walking distance to most of the Viennese sights and very good tram and U-bahn connection (10 min by tram to Hauptbanhof or 5min to Westbanhof). The flat is very quiet at night and has all the amenities you need, all clean and in perfect working order.
The communication with Teresa couldn't be better either - she replied to all my emails very quickly and thoroughly. I haven't met her, but her mother and brother were both very helpful and nice and made sure I had everything I needed. I also really appreciate that they were so flexible about the check in and check out times. All in all - a great experience, I would definitely recommend Teresa's flat to anyone travelling to Vienna :)