Mario's place is on the rooftops and has a nice view. Although I didn't experience the balcony (because of the snow) it offers something not so common in Vienna.
Minuses: bedroom and kitchen are in the same room and so are the noises from the equipment.
And while it may have been "smart" to put the keys box in between two tiny walls far from the eyes it's hard to reach for the guests and I recommend to move it somewhere else.