Location, location, location! The apartment is very well located, close to several restaurants, bars, and other attractions. A subway station is a couple of blocks away, and you can walk everywhere. The apartment is cozy and comfortable, and Catarina and Jose kept contact at all times. They were kind enough to leave us a bottle of wine (VERY welcome after a long trip!), and Jose spent some time showing us his favorite places around Porto, and the "must-see" places (do NOT overlook the Manteigari! Their 'pasteis de nata' are to die for!).
I recommend them 110%, and we will definitely stay there on our future trips to Porto!