The apartment is nice but several things must be changed: the toilet seat is not fixed, the shower hose cannot be hung, a socket is located right above the bathroom sink... And beware if you are going in winter, the small heaters supplied are not enough when it's cold outside.
Apart from that, we got a very friendly welcome from Maria. Despite our late arrival, she took the time to show us what to do on a map (she speaks very good French), and even brought us some biscuits in case we were hungry. She even offered us to stay one night for free when we found out our flight had been canceled!
Villa Nova de Gaia is a very good place to stay since you have a beautiful view of Porto over the Douro river, and can reach Porto within a 10 minute walk. There are plenty of restaurants next to the apartment.