The apartment is located in very good place, close to Karls Platz (communcation hub of Vienna), walking distance from the Opera and across Vienna Polytechnic. Naschmarkt is just 100 m away. The hosts took very good care of us and we received from them regular emails updates about their favorite places to eat and how to move around Viena. They even have a portable WiFi access point you can take with you when walking around Vienne.