Silvio's place is well stocked. He and Adriana have thought of everything to make their guests comfortable, from providing an array of breakfast foods to having a hair dryer in the bathroom.
Adriana checked us in personally, giving us lots of amazing tips on where to eat and what to do in Porto. (Try the restaurant Flor de Congregados. Amazing!) She was warm and friendly, and was available throughout our trip whenever we had questions. We just messaged her on WhatsApp.
The location of the apartment is great. It's 7 minutes walk to Rua de Santa Caterina, the many shopping street, but enough away from the bustle that you can get a good night's sleep.