This place is brilliant. So well located - a short tram ride from the centre of town. The rooms are beautiful. We stayed with four older people, one of whom has minor mobility issues. Ferdinand and Lieschien were up front and accommodating, letting us leave bags after checkout (the apartment is on the way to the main station from central Vienna), and were able to reassure us ahead of time about accessibility- not a given in Austria. There are stairs from the bedrooms to the beautiful living/dining area, but they were up front about that and we were able to work with it. The lift to the apartment helps no end.
Highly recommended.