First of all, María is a wonderful host who makes you feel right at home the moment you walk through the door. She welcomed us with excellent Port and gave us a quick tour around the place.
The apartment is perfect for a couple to use as their base of operations in exploring Porto or simply as a place to just chill. The apartment is spacious (and smells wonderful!). The bed is comfortable, the kitchen is very well thought-out, with excellent use of space and anything you might need - washing machine, fridge, microwave, oven, hot plates, water boiler; and the bathroom is very roomy and pleasant.
Close to the apartment is a large shopping mall with a huge supermarket, there is a smaller supermarket even closer, and the metro station is a minute away from the building (it takes slightly over 5 minutes to get to city center by metro). Alternatively, you can walk to the city, it's a downhill walk and very pleasant at that.
If I ever return to Porto, this will be the place I go to, definitely.