Our short visit to Oporto has been a great experience thanks to Mariana´s apartment.
The location is very good. Is not in downtown but you have Casa do Musica´s underground station in 5 minutes walk and another 5 minutes by train is what you need to get in the city center.
The area is quiet and you can also find cafes, supermarket, shops, and so on.
Mariana and her family are kind and friendly people. They would help you with any tip that you need.
The apartment has all the commodities that you need to enjoy your stay.

We would honestly recommend this option.