Five stars all the way! If you are going to stay in Vienna do yourself a favor and stay here to get a real feel for the entire city. My wife and I stayed here for 3 nights and the place is just beautiful, clean and spacious. Our host Andreas was very responsive and had great suggestions.
The apartment itself is in an old palace and is the top unit in the building. The location cannot be beat. It is centrally located in the heart of Vienna; it's literally like staying in the Viennese version of Times Square in New York City. This apartment is right by the Stephansplatz train station which will take you anywhere in the city you want and is very, very easy to use. You are only a 5 minute walk to the canal with its amazing nightlife. My wife joked that being in Vienna was like being in a birthday cake because of how ornate all the building facades are. We just found ourselves wandering street after street just taking in the sights. This was a great place to be for our trip to Vienna!