I think that are two components in all this: the host and the apartment.
André, the host, is a great one! Before even arriving in Porto he gave us great recommendations for what to see, where to eat in Porto etc.
Also he informed us that during our stay will be some noisy construction. Very communicative, André made the check in/out easy and pleasant.
The apartment (flat) is extremely well located; secure and with all the major sites in the walking distance. Clean and conformable the apartment is as described. The apparent is bright and well appointed.
100% recommended; we will return!