We had a perfect 4-night stay at Francisco's apartment. Everything was as described here. There was one bedroom, one living room with kitchen and one bathroom. Each room has a balcony. The wifi worked perfectly. The main attractions were easily accessible by walking, there were cafés and restaurants nearby, the apartment was clean and equipped with all you need for a short time stay. As a woman I greatly appreciated there was a hair dryer provided :)
The elevator in the building was out of service a few times but it didn't bother us as the apartment was on the second floor. As a side note, in Porto you can expect garbage collection or street cleaning at 11 pm so be ready for that because the buildings are not very well insulated.
Francisco was available to answer all our questions and checked us in at 10 pm. Thank you very much for everything, we would definitely come back to stay with you again!