Mario’s flat is clean, with simple but pleasant furniture, very well appointed (with just everything you could need in the kitchen and bathroom), well located in a nice neighborhood (near the Danube, city center and very very close to the métro station on the U4 useful to visit Vienna) and very calm. You can ask for another single bed which makes it a very good price option. Mario is very diligent in answering. (Only caveat : there is no efficient way to block the sunlight in the morning if you need pitch dark to sleep.)