Lovely stay at Joao's apartment. We really appreciated that he waited for us with no extra charge on a Friday night (our flight was put back and we arrived just after midnight). The apartment has everything you need. A well stocked kitchen with all the utensils you could need if you wanted to cook, a great shower and a comfy bed, plus it's really spacious.
You're right in the middle of the city, directly opposite the #1 rated restaurant in Porto (Muu steakhouse - highly recommended!) and around the corner from loads of great bars.
We happened to stay the weekend that Porto won the league and it was very noisy at night, it wasn't too much of an issue for us as we like being in the thick of things but maybe not ideal for people who want a peaceful weekend. Highly recommend the apartment and we would stay again.