Didn't really enjoy my stay there, a lot of issues with cleanliness of the place: bed sheets were covered in sand, hair and blood stains. Lots of hair on the floor. Towel were smelly. Bathroom hasn't been thoroughly clean. Pillows were uncomfortable to sleep.
There is a dog living in the apartment that howls all the time, at night too.
Also take into account that city center of Porto is 30min away by train, which arrives once in an hour.