Clean, spacious and well-appointed flat in an excellent location. We used it for a working visit to TU Wien which is directly across the street. There is a desk and good wifi in the flat, and it's on the fifth floor (with lift access) which means that street noise is minimal. It's also very convenient for the Naschmarkt, which is just around the corner, so there are abundant options for all meals, including breakfast. It's only a short stroll to the centre of Vienna, a number of museums and galleries, and close to a U-Bahn station, so it would be an excellent choice for a tourist trip as well.
One minor thing to be aware of is that the WC is quite small (not unusual so for city flats) and will be a tight squeeze for someone large or with mobility issues.