I wasn't sure after sending the first message to Patricia, i had to send a second message to check if she received it. Turned out she did and since then she was responding almost immediately. I was coming for a very short visit (1 night only) to Vienna and arriving before the usual check-in time at this apartment, but also checking out early in morning. Patricia was kind enough to make it possible for me to check in earlier.
The apartment is very well located - just 1 min walk from Stephan's platz. There is elevator, bathroom with shower, toilet, small kitchen with table and a sleeping/living room with double bed, and sofa and a big closet. The house was clean and nicely prepared (even the guidebook to Vienna in English language version was awaiting there as reference material). The building has an elevator so it's very easy to get in. Key was left precisely as described.
The only negative sides were the fact that bed sheet had a stain like a hard to wash one although the sheet was definitely fresh (fresh washed).
It would be useful to know in advance what kind of coffee machine is in the house, so one can bring own capsules. But also: so many cafes in Vienna that it's as if a sin to drink capsule-machine made coffee ;)
I am very glad i had chosen this airbnb place and i'd happily stay there again when in Vienna.