We had a great time at Klaus and Stavroula's.
Unfortunately we were a bit on a schedule due to the short duration of our stay, in turn due to an ongoing infamous pandemic that shan't be named... So we didn't get to spend much time with them and met Stavroula only briefly ; unfortunately it seems she was away for most of the duration of our stay. Klaus was working the night shift, so we only got to chat a couple of times. Nonetheless ! Klaus is very welcoming and sympathetic, he knows a lot about many subjects so you'd be hard-pressed to not get along with him or fall short of a topic to discuss :-)
The room they gave us was beautiful and mostly clean (there was a bit of dust here and there, but nothing dramatic), with everything ready for us : clean bed sheets, a solid amount of towels and there was also a lot of furnitures to unpack our travel bags into. The only issue we had was with the shower, at some point it got clogged and overspilled, which dampened our towels that my ladyfriend had put on the ground next to the shower. But Klaus fixed this right away and provided new, dry towels. The matras was a bit thin and you can feel the slatted base underneath.
In the kitchen, there is free food, both left by previous visitors and bought by Klaus and Stavroula ; should you wish to have breakfast at their place. I find this attention very touching and I appreciated it a lot, although we preferred to have a go at the *many* cafe/konditorei that one may find in Wien. ( Our favourite was "Zehnsiebzig" -> https://g.page/cafe1070?share )
Regarding the neighborhood, it is full of shops and small businesses, restaurants etc. and seems fairly new ( late XXth century ). You'll find a lot of place to go for a drink or eating, etc. Also, the public transporations are plenty and very close by, there is even a streetcar stop almost right in front of Klaus and Stavroula's apartment !
One more thing you should know : the floor is made of old parquet and it squeaks, so if this is the kind of thing that annoys you and/or prevents you from a good night's sleep, you may want to bring earplugs for the night. We personally didn't mind, my lady and I :-)
I hope to come back soon and would definitely stay at Klaus and Stavroula's again !