Bernhard was absolutely amazing. From the first conversation onwards you could feel that he cared for his guests having the best possible experience. Always on hand with advise he made the stay most comfortable. His flat is highly recommended. Brilliant location, beautifully designed, spacious yet still very, very homely. If there is one little thing that I would change its that the signage to the flat once inside the courtyard. Naturally, one would look for the part of the apartment that holds room 35 but it's a little confusing until you realise that you have to take the first door on the left once inside the courtyard to go up to the 5th floor which can be frustrating if you have come from a long journey and just want to get into the place and rest.
Other than that, definitely book this place if you are going to vienna.