Very nice stay. We spent New Years Eve in downtown Vienna. The host and check in was quite friendly and easy to work with. Good , clear instructions. One of the "bedrooms" is also the "main room," so if you have a lot of people, some may still be sleeping in a room where others are up. The rooms are VERY big, however.
Biggest challenge is parking (we rented a van and drove), so be sure to map out a few possible garages before hand. You will need to do public parking.
All in all...very good experience!