Ron really cares about his guests, this was probably the best organized Airbnb I've been in. He was very helpful throughout and communication was super easy. The location is great, perfect for walking to the city center and right next to the Naschmarkt.
We had a slight hiccup due to the Nuki system updating which lead to us not being able to open the front door of the building. Fortunately somebody let us in and it afterwards got solved pretty quickly, but it should be noted that you need to have Internet access to be able to activate the locks.