We stayed in Claudia's place for 3 nights. And it was amazing. She messaged us 2 days before check in with complete guide of how to use everything. Apartment is in a really good quiet place (close to Dunai river and Prater) inside the old building, which is only making it better!
Apartment itself was really light and clean. The only minus is, wi-fi password is wrong, so it's impossible to use wi-fi inside the apartment.