In a way, this place was a lucky strike for me: It is listed as a shared bedroom, although it's actually a private room; the location is amazing, great for exploring both the classic Vienna sights and hipper places in the 6th/7th district; it was very quiet; there is a really nice desk, chair, and good internet in the room for working remotely (although none of this is indicated in the listing); and the (~1900 Altbau) building where the apartment is located is just drop-dead-gorgeous.
Now the downsides: While the cleanliness was okay overall (bedsheets and towels were fine), the apartment really needs a deep clean (dead plants, dust everywhere, spider cobs); especially the bathroom was quite messy. The room also smelt terribly of cigarette smoke when I first entered it (but this went away). Kitchen had no microwave and there was a lot of trash. The fridge, bathroom, and hallway were full of personal stuff. This place needs better organization as to which space is reserved for guests and which stuff guests are allowed to use.
What I disliked most however was that I was never introduced to the other inhabitants that I shared the kitchen and bathroom with (it seems to be another AirBnB double room and one permanent resident). I also had the impression that the permanent resident was bothered by my presence which did not exactly make me feel welcome (but it didn't bother me either). So while I was overall happy with the stay, I think it needs some cleaning and better management. If you are laid back, you will be fine with staying here.