We loved this apartment in Vienna. It really was a comfortable space, one of the most comfortable we've had in fact while traveling extensively through Europe in over 15 cities. The staff at Validus is kind. It's also nice that their offices are in the same building and same floor, so check-in is very easy.
This building, right by the VotivKirche church / cathedral, is simply beautiful and very cool. Even the elevator is unlike any we have been in before.
For the important items, the WiFi and A/C work great. The apartment is quite large and spacious with a nice TV. We even found the murphy bed quite comfortable, and a better mattress than many regular beds in other Airbnbs. It's also about a block from the metro which has a decent mini-market type store and some quick bite restaurants in it.