We stayed for a couple of days at marios place and enjoyed it very much. The flat is beautiful and central next to rua santa catarina so you can walk to all the bars, restaurants and sights of porto. Mario was very welcoming (even though we arrived late) and helpful and gave us lots of information and recommandations about porto. I think the appartment is perfect when you're looking for a central place where u can find privacy and rest after exploring porto.