I've been staying in Erwin's apart for two weeks, and it was fantastic time. Location is super, just 7 minutes on foot to nearest stations Volkstheater or Neubaugasse. Also there are a lot of nice cafés and bars hear, 5 minutes walk to Mariahilfer Strasse. Room was clear and lovely, it has enough space even for two people staying there. Erwin is a very nice guy, very helpful and with sense of humor, I didn't have any problems. It's a perfect place for students (like me) and couples.