The location of the apartment is great, it can't be better - very central and very close to Stephansdom. Check-in was very convenient as the host provided a PIN code for accessing the apartment. We were also able to deposit our suitcases before official checkin as we arrived with an early flight.
The apartment looks better on the pictures compared to real life, we were disappointed by the condition of the kitchen and the bathroom. Many glasses inside the cupboard of the kitchen were dirty despite being in the cupboard and the dishwasher was still full with dishes after checkin. The toilet seat wasn't properly fixed and one of the electric outlets was broken and looked quite dangerous.
In general I would say that the apartment has a lot of potential but it would need a little additional investment.