The building has a lot of Viennese charm, though the interior is currently being renovated (so no elevator, and some reno noise during the week days. We were out discovering mostly, so it didn't really bother us).
It's located in a convenient area, with easy access to a lot of public transit options within a short walk. We got the multi day pass which made sight seeing around Vienna very easy.
The unit itself is quite big with an interesting layout. From the front foyer, you can access the toilet room on one end, then smaller bedroom, then in a fun loop, the living room, main bedroom, shower room, dining room then kitchen. It had everything we needed for our short stay. Keep in mind that the floors are creaky, and sound travels well even from the halls (we're more sensitive to that because of our toddler). oh, and the wifi was quite slow...
The host was friendly and responsive. Check in was done in person so it took a bit of coordination, but check out was a breeze. She even let us keep our luggage there for a couple of extra hours.
Overall we enjoyed our stay in Vienna!