I definitely recommend Ai Porto! to everyone visiting the city of Porto. The appartment is situated in the center of the city and away from the main tourist stream. Therefore, the neighbourhood allows you to interact and blend in with the local people.
When we arrived, Celio was waiting for us in front of the appartment and as soon as we entered the appartment he treated us with good advice, tips and even Pasteis de Nata and Port-wine as welcome gift.
During our stay Celio kept in contact to make sure that we felt comfortable all the time.
If I can be critical, then I have to admit that the apartment was a little bit chilly when we came home after a day in the city. There was an electrical heating system available in the room but we didn't use it much as we didn't spend a lot of time in the appartment (only to sleep).
Summarized, don't hesitate, just book this place and you will enjoy Porto to the fullest.