Very nice and clean place. And spacious!! 10 minutes to the Opera house and the city center. Communication was quick and efficient. Their check-in & check-out hours are punctual as specified in the listing. I did pay extra to check-in fairly late in the evening (11 PM).
Eva provided good recommendations for local restaurants, bars, breakfast places etc. Also great direction to arrive from airport. Very well done.
It is on the sixth floor off of the main street. So open windows will bring the noise. But if the windows are closed then there is no issue.
Highly recommend this place if you are visiting Vienna.