I, my wife, and my parents-in-law stayed in the apartment for 6 days and it is a nice apartment. Diana responded to every message in just a minute. There are lots of restaurants, cafes, and stores nearby. The bus stop is just in front of the main gate. The apartment comes with an air-conditioner but it required to place the ventilation outlet outside the windows and it allowed the noise from the street to come into the apartment. The apartment is on the 2nd floor but the host stated that we should not use the elevator so it is a bit problem to carry heavy luggage up.
Only a few minus points, the 2nd bedroom has no wardrobe or place to hang clothes. The street noise can be heard in the master bedroom and living room but it is manageable unless we keep the window open.
Overall the apartment is very good and located just 1km from the parliament and from there, we can walk around Vienna attractions or use public transport.