I have nothing but great things to say about Mariana and her apartment. The view is wonderful, yes, but it's also well-located in Palermo (near Plaza Italia) and is super comfortable with good security (not that you particularly need it in Palermo, IMO). Supermarkets, gym, restaurants/bars, and subte/bus stops all within walking distance. AC units work great, though thankfully I did not need them much. I cannot really think of any negatives...some people remarked that the elevator is slow. It seems like an odd criticism to me...I suppose it could be faster but I never thought it was painfully slow.
About Mariana herself...extremely helpful and always quick to respond whenever you need her. In every instance where I had even the slightest problem, she addressed/fixed it immediately. This is quite often NOT the case in BA, so I really want to emphasize how great she was during my stay (~5 months).
If you are thinking about booking this place for a trip of any duration, don't hesitate!