We have spent such a good time in Miriam's and Philipp's apartment!
The flat is very light, comfortable, nearby the city centre. It takes 10 - 15 minutes to get to the most popular sightseeing points: Hofburg, Karlskirche, Vienna Opera, etc. Due to the closeness of two underground stations: Rathaus and Jösefstadter Straße you can easily get to the part of Vienna you would like to visit. The tram station is 3 minutes walk from the apartment and we often used it as transport to the city centre.
It was a great pleasure to meet Philipp and Miriam, they are very friendly, open and kind people. We had no problems during our holidays but I'm sure they will do all their best to help you if something happens.
To summarize, I highly recommend this apartment for spending your holiday there, I'm sure you'll enjoy it as we did it.
P.s. Philipp and Miriam have a self-made guide of the restaurants to visit nearby made according their experience, it was very kind of them and, to tell the truth, I was a bit surprised.