First let me start with the good facts:
The apartment is nicely furnished, clean, very bright and absolutely suitable for a short trip as a couple.
The location is perfect! You will find everything you need just around the corner (parking, supermarket etc.). From the apartment you can walk to any location - it's really within the city center.
However there were two facts that we didn't like at all and maybe therefore we wouldn't book it again.
First it's really REALLY noisy also during the night. Although it's a smaller street the traffic noise is very heavy from the street nearby (leading to aliados). You really have the feeling that you sleep on the street.
Second the bed is really really small, it cannot be considered as a double bed (approx. 1,40m x 1,80). On top of that it's a very bad mattress, you can literally feel every metal spring jabing your ribs.
However we enjoyed our stay as porto is a nice and vibrant developing city.
The service of the "Porto Concierge" worked quite well. The check in was really on time and the host who explained the apartment was very friendly. However if you expect the typical airbnb local experience with a local host explaining everything about the neighborhood there is certainly space for improvement.