Pick this one! It is very well located, walking distance to everything. 2 blocks from Livraria Lello, for instance, and from there you can walk to the other places. We didn't get the car for anything in the Porto/Gaia main tourist area. Parking is below the building (Palacio de Justiça) and they will give you a parking card (so you don't need to pay). Bathroom is spacious. Everything was good.