One of the best Airbnb I've been to !
The place was perfectly clean, there was also a free map which is a great help for visiting the city.
Bed is also very comfortable and there is everything you need, towels, cutlery, ...
Most importantly the location is just perfect. From the apartment, you can visit the whole city by walking.
Also in the street of the apartment, there are multiple restaurants, including a pizzeria which is one of the best in Porto.
I would highly recommend this flat :D