Cozy flat with a central location (took us on average 15-20 mins by foot). I stayed there with my girlfriend for 3 nights. We loved that the flat is spacious, tidy and especially very well-equipped. On the latter point: washing machine and ironing board are getting especially helpful when things with coffee go wrong on your shorts.
One thing we disliked specifically about our room, somehow we felt strong cigarette smell from time to time in there.
Nevertheless, very friendly and responsive host! We had positive experience with Roman and Alina and can only highly recommend them and this apartments. On top Roman provides you with significant tips around Vienna.