We enjoyed staying at Mario's apartment. It's in a good location, close to metro and the main tourist attractions. There are good restaurants and patisserie shops close to the apartment to ensure you enjoy local food/desserts. The flat was clean, tidy and as described. Although we arrived to the apartment earlier than the check-in time, Mario provided us the information that allowed us to access the room to leave our luggage which was very convenient. He also kindly left us food vouchers and maps which were helpful. The only issue was the noise at night times by the university students and some locals, which is out of Mario's control. Overall, I would recommend his apartment to anyone who'd like to visit Porto!