We had a wonderful week in Porto in Rosario's apartment. It is located in a quieter part of the City, right on the ocean side. There are also several nice cafes and restaurants with an ocean view. We did not use public transport, but a taxi to Reberia district (old part of the city), takes approx. 15 min a costs 7-8 eur.
The apartment itself is well equipped with everything and has a nice living room. It is a bit narrow for big guys but is very authentic :)
Rosario is a wonderful host that was very flexible with our check-in and provided everything we needed for a good stay.