My fiancé and I were in Vienna for less than 48 hours and needed an easy place to stay. The room we rented with Klaus was a great value for what we pic for. It was clean, relatively easy to get to and from, and pretty much as pictured. Klaus sat us down on our first night and gave us a great map of Vienna with a list of lots of things to do. We pretty much got what we expected with a shared room.
The only thing to really make note of, not necessarily a complaint, is that the apartment is pretty old with creaky floors and doors connecting all of the rooms. Because of this and our late nights and early wakeups, we were definitely apprehensive about how much noise we were making even just walking around, as we didn't want to be disruptive to the other folks in the flat.
All in all, exactly what we paid for though - basic shared room with access to basic amenities for a quick stay in Vienna.