This is a great apartment in a very good location. The design and decor are fantastic, and the location just by the Donaukanal gives you great access to the canalside amenities, Vienna's historic centre and the nearby Karmeliter market. We really enjoyed walking along the canal and going to the cafes and restaurants in the market. Roman also provided us with all the information and support we needed, including some great tips for places to eat and drink.
There were just a couple of minor downsides, mainly due to the time of year that we visited: first, as an older apartment it doesn't have air conditioning and because there was a bit of a heatwave in Vienna at the time we had to run both of the fans provided nearly all the time. Second, the heat again meant that we had to keep the windows open at night, and there was a lot of traffic noise from the nearby main road. At any other time of the year neither of these would have been problems, I think. Overall we would really recommend this place!