I stayed for a couple of days wit my family at Joao's place. The location of the apartment is fantastic, just in the right place to know Porto mainly by foot, take a boat or a train to do a small tour. Joao's advise was great ! He is always available for any question and give you a complete info for what to do and where to eat :o)
I will fully recommend him and his place to stay and if we came back we will contact him for sure !!