I will be recommending Validus to everyone I know who is visiting Vienna. Very kind and informative staff, VERY clean and quiet building and a prime time location (walkable to everything). We got locked out of our room one night and since the hosts do not live at the property, we had no idea how we were going to get back in. Within 5 minutes of calling the phone number provided for Validus house, the building manager had us back in our room and on our way exploring Vienna. I would highly recommend to anyone.