The stay at Baxia24 was really good.
When we arrived we had some problems because the bedroom that they give us was occupied by another couple, but I text Mario at midnight and he text me back straight away.
The self check-in is really easy and helpful for someone like us that’s arrived at 22:50 at the airport.
The room is really in the center of the city of porto and the metro and bus station is about 1/2 minutes walk.
If you want to come to porto I recommend this Airbnb, but is like a big apartment with shared bathroom, kitchen and living room.