The good stuff: I was traveling with my wife and 2 kids. The apartment was great because it's spacious, so we never felt crammed. The communication with LovelyStay (the team handling this apartment) was always great. They were responsive and helped us with anything we needed (for example, we needed to wash our clothes, so they brought us the drying rack). The living room, the huge dining table, and the balcony are all really nice. The apartment is right next to a busy road, but it's not that noticable, because the balcony is turned away from the road. The location is really great, especially if you have an event in superbock arena. It's also just outside of the busy areas (it always felt amazing to come back from the city center into our quieter neighbourhood), but still within walking distance of everything.
The bad stuff: when we arrived, we noticed the apartment wasn't properly cleaned. We let the team know and they apologized and organized the apartment to be cleaned the next day and handled the situation very professionally. The apartment has a bit of a bad small (smells damp). This was improved after the cleaning, but came back after a few days. It's the worst in the smaller bedroom (which by the way is really small - there's basically just enough room for the bed and that's it). The smaller bedroom is also right next to the road, so it's a bit noisy throughout the night.
The view from the balcony is really great on one side, but it's also overlooking some very overgrown (and not very nice) garden and a (what looks like) a collapsing next-door building.
The yellow bathroom probably needs either some deep-cleaning or renovation, because the caulk between the tiles is black from dirt (or mould, not really sure what it is), which makes it very unappealing.
The wooden floor throughout the apartment feels a bit unsafe, as it's bending in a few places and there doesn't seem to be anything underneath the wood.
Oh and note that the check-in takes place in a different place to where the apartment is.
Overall, this was below average of what we're used to, but I'm not sure how it compares to other places in Porto. Looking at the buildings it may very well be, that this is just what most places are like.