Oporto Rental Management are the absolute best! We only had 24 hours in the city and were very impressed by how thorough the management company was checking us in. They offered a driver from the airport which we were glad we booked because it got us into the city very quickly and saved us a lot of time getting lost in the mass transit.
Rosalia met us at the flat and gave us a tour of the apartment and gave us a map highlighting all the "must see" spots in the city-- tailoring it to our tastes. They even let us check in early so we didn't have to lug our bags around the city all day which was amazing.
The apartment is in a great location, close to all the action and very walkable. Definitely bring your walking shoes though because Porto is very hilly! We would definitely stay there again! Abrigada : D