We had an amazing 6 days hosted by our fantastically thoughtful hosts. They are a mine of information about Vienna and the flat is a very short walk from the main art gallery and Natural History museum.
You just need to be aware that the apartment is on the 4th floor (there is a lift) and the room is in the loft space so headroom is limited in some areas. The hospitality, care and consideration shown by our hosts was impeccable throughout.