The apartment is cozy and roomy enough for 4-6 people. If you are driving it's a sweet spot, as you're only 10 minutes away from downtown and the ride itself is a nice sightseeing, with a closed parking place as a plus so you don't need to worry with your car on the streets.
Our host took good care of our needs during our stay, and things have gone smoothly all along the 4 days we've been visiting Porto and neighbor cities.