Our stay at Zoe's was perfect. The flat is in a residential area and away from the buzz of the city. The tram stop around the corner takes you to the underground stop in just a couple of minutes, and therefore at Stefans Cathedral in no time.
The flat is clean, and has all you need for your stay. The bed is comfortable and quiet (we did not hear the neighbours at all).
The balcony is just the place for a glass of wine to unwind at the end of a hard day in the city.
We would definitely recommend Zoe's apartment, and will be looking her up the next time we are in Vienna.