We stayed in Roman's apartment for 4 nights and we loved it. The apartment is really cosy, well equipped (it has a coffee machine with coffee included) and very clean. It's a 8m walk to the metro station and the CAT (a train that takes you there in 16m from the airport). There is also a supermarket across the road.
We were a bit surprised to see the toilet is across the entrance hall, although is is written in the apartment description. That wasn't a big of a problem for us, in fact it has its advantages, just leaving the note for other people to be aware of it.
Communication with Roman was nice and efficient.
We will definitely stay there again and we highly recommend for anyone who wants to visit Vienna!