We were 2 persons staying in Ilana's flat for 5 days and everything was perfect there!
We didn't have the chance to meet Ilana but her husband welcomed us and was very nice and helpful! Ilana was really responsive to all the mails and gave nice advice!
The flat is close to the center (we actually never had to use the subway or tramway..only to go to our car). If you come by car you can park it at the P+R parking in Ottakring and the tramway drive you just in front of the flat.
I strongly recommend this flat and I will for sure book it again if I have the chance to go back to Vienna!