We had a nice stay at Rafael's house. It is very well situated, a nice 15-20mn walk from the city center and 5mn walk from public transport. The apartment itself is quite large and spacious, and Rafael's communication was reactive. Very easy check-in and check-out. Only little issues were the relatively bad sound-isolation (although the street is generally very quiet) and the lack of storing place for clothes (as most of the furniture is occupied), but you might not find this problematic if you're there for a short stay. Overall a good option if you're going for a short stay in Vienna.