We had a nice stay at Claudia's. The apartment is located in a quiet residential neighborhood near the Foz do Douro and the beach. The city center is some 10-15 minutes away by car, which was not a problem since we brought our own. It is nice and cosy, but quite spatious and well equipped. It has two balconies, one of them with a wonderful view of the sea.
Claudia is a great host who speaks fluent English and was welcoming and helpful.