We thoroughly enjoyed our stay at the Hungarian Biscuit Apt. (3 nights) Well equipped and located in the center of town. Not to mention you can't beat being above the bakery. Elisa's help on checkin and communication was greatly appreciated. In addition, the staff at the bakery were all very friendly & helpful on any interaction.
If you are driving into town just plug in Praça de Lisboa. They charge 20€/24 hr., but you can try to book it on the internet and I think it is 15€.
Previous reviews mentioned the noise but we didn't have any problems. An extra fan in the bedroom & we always use a white sound app on our phone(s)
We recommend Elisa & Luis's place in Porto.