We stayed in Harry's apartment for 3 nights at the end of august. The flat was clean and big.
The price was good for Vienna.
The location is good not in the ring the center of Vienna but very close (3 metro stations away) and there's also a tramway stop in front of the apartment. But after 10pm everything is close and very quiet in the neighborhood.
You are also close to the train so at night and in the morning, you may hear the train.
The communication and the checkin could have been better, Harry was not in town but the cleaning lady was there to welcome us and give us the keys.
Overall everything was good and i recommend this place if you go to Vienna.