The location and size of the apartment are very good. You are on walking distance from the city centre (if you book Porto, you know that the roads can be quite steep), lots of nice restaurants and the main sights, however in a relatively quiet street. When you close the windows it's fine and some sound is inevitable in a big city.
Across the street you can buy bread and there is a small supermarket. A bigger supermarket is also close by.
The rental office is underneath the apartment and the staff is very friendly and helpful, so make sure to ask them if you need any assistance. Apart from some issues with the shower, which we already communicated to the office, it is a nice apartment to use as a base to visit Porto.