Helena's apartment is very nicely located with plenty of restaurants, bars and shopping opportunities within walking distance, but still in a quiet area without any noise from the street.
The apartment itself is nicely decorated and perfect for 2-3 people, with a huge bed/sofa and well functioning kitchen and bathroom.
Helena is a great host and provides a brilliantly constructed map of the city with highlighted recommendations of everything from restaurants, museums, shops and suggestions for bike routes.
We also rented Helenas two bikes, but found the quality of the bikes to be quite low. So if you plan on biking a lot around the city for more than a day, we would recommend renting some bikes elsewhere. However, this does not change the fact that we had a great stay at Helenas apartment, and would not hesitate to rent it again, should we come back to Vienna.