This is a great location tucked up in the hills behind the port warehouses on the south side of the river. In touring the city, we were never more than a 6-8 Euro taxi ride away from home and it takes about 15 mins to walk to Ribeira. The apartment building itself is located on a quiet residential street. It's a bit of a walk to nearby stores and restaurants, but they are still accessible. The location is very convenient to Estacao Vila Nova do Gaia.
The apartment has an amazing view from the kitchen and living room. Host Nelia was really sweet and left us some bread and spreads to snack on as well as coffee and beer - you know, the essentials. Nelia was also super helpful in letting us check out a bit later so that we did not have to haul our bags around town before our train.
This is a great location if you think you'll be spending most of your time in touring port houses or if you don't mind staying a bit away from the center center if it means you'll have a great view.