I want to preface the 3-star rating is in no way a reflection on the hosts (Johannes and Johanna - who were wonderful, super communicative and helpful). It's rather a feedback on the situation/location of the apartment, considering the very hot weather that Vienna has been experiencing while we stayed at the apartment in late July/early August 2022.
As previously mentioned, the hosts were wonderful - very responsive, helpful and made the check in process super easy. They were also helpful in providing additional information regarding best ways to get to the apartment and go to locations around Vienna.
The apartment itself is located in a great neighborhood in the Inner Stadt with lots of restaurants and walking distance (or a short subway/tram ride) from many of the location around Vienna.
However, the apartment is not equipped with air conditioning. In order to keep the place cool, while staying there, we had to keep all the windows open. Unfortunately, that's not super helpful as the air does not have a way to circulate (there are 2 standing fans in the apartment - but those do not help enough). So, due to the hotter weather in Vienna during our stay, it would get pretty hot and stuffy in the apartment. Also, being located in the more fun/happening part of town, with lots of night time activity, we found ourselves getting woken up on Friday and Saturday night around 4 AM with the nearby club closing down and happy/drunken people being loud/screaming while leaving the club.
I would definitely stay at this apartment again, but NOT during the summer/warmer season.