A good choice for travelers to Vienna. near to means of transport , especially the metro line U4 that reaches to almost every city attraction. the neighbourhood is really good with supermarkets, restaurants and banks. Mario is very reachable and answers the messages within minutes in case you need anything. He provided us with items that was missing from the apartment within few hours writing to him.
I had the feeling that the apartment has the potential to give more efficient space with the right choice of furniture , but it won't be a problem if you're there for few days. Also make sure to ask Mario about facilities provided in the apartment in case something is a-must on your list ( eg, a clothes dryer was listed on Airbnb but there wasn't one) . but like I said, minor things that won't affect your trip nor your stay.
A good choice.