This apartment is perfect for a couple for a long weekend (which is how long we were there for) - it is centrally situated, so can walk to all the good places easily, but found on a side street so not overwhelmingly busy. It was super clean and well stocked up. It felt like home for our stay.
André is one of, if not the, best hosts that I have had the pleasure of meeting through airbnb. He went out of his way to make our stay special - before we had even arrived, he had sent me recommendations of things to do (a walking tour, places to eat and drink). He was super responsive when I accidentally locked ourselves out, and even gave us a lift to the ocean front. Basically a really nice genuine guy and a bit of a legend.
Go to Porto - it is an amazing place, great food/drink, super friendly people, plenty of culture and great value. You will not be disappointed.