We stayed 2 nights in Mario's apartment. The room was clean and very well located. Breakfast was included which was really nice. Because our room was on the side of the street it was a little noisy (I am sure it would be the case in any other apartment in the Porto centre). This apartment also had other rooms which seemed to be on the side of a quieter street but unfortunately they were taken ! Though we did not meet Mario in person he answered all of our messages really quickly and spoke to us on the phone which was appreciated. I would recommend this place for a short stay in Porto!