This appartement belongs to some sort of agency, (is that even legal?) so don't expect to have any kind of welcome or to meet someone from the city if that's what you're looking for. When we arrived, we had to get the keys in a bar where we waited with different groups of people for someone to come for the keys. She was supposed to arrive at 14h, and insisted many times on this, but still arrived at least 20/30 minutes late. It was an awkward moment, not gonna lie.
The flat itself though is fine (if you don't mind the strong smell of bleach), it's quite comfortable and nicer in real life than in photos in my opinion. The location is perfect to visit Porto by foot.