Sofia's apartment is extremely well located. Right in the historical center and in a pretty quite street. Everything is at a walking distance and this allows to lie the city at best. The apartment is nice and well equipped.
Be aware there is no centralized heating although electric heaters were available in the apartment. We were expecting a bit warmer temperatures in Porto but during our staying (end of March) these were instead a bit low and also the apartment was cold. The available heaters helped but they could warm the rooms only slowly and for safety reasons we didn't want to keep them on while we were out.
For the same reason the bathroom was a bit humid, but, again, that should not be a problem during the warmer season.