We didn't meet Mario but we were welcomed by a very nice colleague of his who took the time to make recommendations about things to do and see in Porto. The room was in beautiful condition - very clean, the view is even better than the photos and we even received a welcome mini-bottle of port wine! The location is indeed superb, being positioned very well for easy and relaxed walks to many destinations in town. The only thing I would note for other interested travellers is that this is indeed a studio - there is not much room to move about, the bed takes up the majority of the floor space. We stayed 4 nights however and were very pleased. Warmly recommended!