The place is amazing and I recommend it with pleasure.
Markus was very friendly. He checked in us in person and spent some time to introduce the house rules, public transportation and the neighborhood.
The location is great. It is located close to (2-4 minutes walking) a few tram stops that connects you to everywhere directly or via one or two connections. It is located on the 5th floor (don't worry, it has an elevator) with an amazing view of the northeast part of Vienna, the famous view of sky scrappers.
The place was sparkling clean. It has everything you need for a short visit, from towel and bed sheets to washer/dryer to tee, coffee and even beer.