Booked through British Airways Holidays. The hotel was clean and well equipped (heating/air con in room with cable TV) and only 10 minutes walk from the Ring Strasse in central Vienna.
Breakfast, included in the room price, was a self-service buffet with loads of different breads, cheeses and cold meats as well as fruit juice, coffee, etc... all of a high standard.
The staff were helpful and friendly, especially considering we checked in at about 11pm! We were allowed to leave our luggage there after we checked out, the staff storing it securely.