The VELO-City Center Apartment is a very good flat to stay for a couple of nights in Vienna.
Actually I'm sorry for I can't give them five stars, but there are 2 things that I wasn't happy with.
There was a problem with the router, so we didn't have internet when we arrived. The host was super friendly and get response immediately, however they fixed it on the second day late afternoon.
The other thing is the bed because they have 2 single mattresses on the bed which are moving easily, so not the the best for a couple.
After all, I would definitely recommend this very stylish and super clean flat if you need accommodation in Vienna