I went to Vienna with my sister for 5 days and we stayed at Felix's place. It was a very good experience. Felix and Iker are super friendly and uncomplicated. The location of the apartment is perfect for young people travelling to see vienna. The touristic city centre is in a few minutes walking distance, but also the Neubau District is very close and even more interesting than the city centre for young people... :) The house itself was also very good, everything as in the pictures and also very clean. Almost a "hotel-feeling", since you have a lot of privacy and the bathroom looks quite fancy :) All in all, great hosts, great apartment, great trip!