We had a great stay at the apartment. It's in the heart of the action in the Ribeira historical center and it was easy to walk across the Ponte Luis I bridge to get to the port houses in Gaia.
Claudia welcomed us with a bottle of wine, helped us carry our luggage up the stairs and spent time reviewing a city map with us so that we felt oriented. She gave us some fantastic restaurant recommendations - Taberna dos Mercadores, which is right next door to the apartment (be sure to make reservations as it is a popular spot), Ze'Bota, Café Santiago (for Francesinhas - an iconic sandwich), and Natas D'Ouro (for delicious custard tarts).
More about the apartment - it's on the third floor, and there isn't an elevator, so if you aren't up to climbing stairs it's probably not the place for you. Also, because you are in the heart of the city it can be noisy at night. The apartment is not air conditioned, but a fan is provided and there are large windows you can open to get a breeze.
Apartment is well-furnished with kitchen items (but who wants to cook in on vacation?!) and has a small washing machine which was terrific. You can hang your laundry on a line outside the windows (clothespins provided) to dry.
We had an issue with the toilet running/tank not completely filling and Claudia responded immediately, bringing a repairman to the apartment to fix it.
We would definitely rent the apartment again.