Mario’s flat is really perfectly located in the center of Porto from where you can walk to any place of the city. Mario has a real sense for advice and I would totally recommend his app. The flat was very clean and the little balcony with almost no view on other buildings is appreciable. The only negative thing would be that from the bed you hear pretty well what’s going on in the staircase which can be disturbing when you come from the countryside as we do ^^ But for the time we had in Porto it was a perfect stay and Mario is available if you have any questions and all instructions he gave us were really clear and easy to understand. We recommend it!