My sister and I had such a great stay at Karlsplatz! The location is very central and within walking distance to most attractions, yet is also tucked away a little so that you are not overwhelmed by crowds. The apartment itself is in a safe building and is clean, fresh and the perfect base to come home to after exploring the city. Christopher was the perfect host, giving us information about Vienna and offering help whenever needed. The portable internet modem is also very useful for exploring the city!
I would highly recommend staying here, thank you Smart Apartments!