Vienna is a great city to spend (more than) a few days and Roman's apartment made us enjoy our stay even more.
Location is very good, a small walk from the metro or straight from Innere Stadt. The apartment complex is just off a main street and it can be noisy (lot of speeding traffic in Vienna, what's up with that?). However, we easily managed to sleep with the window open, as Vienna seemed also quite calm at night.
Once you're in the apartment, you're in the 70's. The style is all there, the comfort of the furniture is of modern standards.
There is a lot of cabinet space, in kitchen, living and bedroom. Also two tables (kitchen and living) make it easy to have a place to eat and work and/or play a board game.
Bathroom is quite small, a shower means getting into the bath tub. Not a problem for us, but good to know. Bathroom, toilet and kitchen are very clean.
Though we scarcely used them, all kitchen facilities are there. Be warned about the coffee machine, it makes a great espresso!
We didn't meet Roman in person, however the entrance/key self service and Roman's helpful communication were more than good enough.