Justina's place is great - central location (couple of stops on the U-Bahn to the Innere Stadt) but on a nice quiet road in a decent neighbourhood. Short walk from Hundertwasser Haus and (even better) Prater Park. Not too big but really cosy, clean and friendly inside with nice art on the walls. We didn't get to meet Justina sadly but she left very clear instructions on how to get the key to the flat. Everything was exactly as described, with some lovely surprises left for us too. Would happily stay there again!