Great apartment - clean and well presented - we felt very 'at home'. It was really close to the river and there are some great restaurants within a short walking distance. I'd definitely recommend this stay for Porto.
Please just be aware that you cannot drop off your luggage outside the building without receiving a fine. If you are travelling by car arrange to park in one of the local car parks and walk (approx. 10 -15 minutes downhill) or park and arrange a taxi to the apartment.