This apartment is in a great location! Everything is a short walk away. It is bright with a spacious kitchen. There's a large enclosed balcony with a great view. The balcony isn't set up as a place to hang out though.
Check-in is by appointment. Someone meets you there at the apartment to usher you inside and walk you through the apartment. We were very delayed coming from the train station, but Claudia graciously waited for our arrival. She gave us a map and talked us through Porto, the sights, and our neighborhood.
Check-out we just left our keys inside. We had a later flight, so stored our luggage at a hostel 2 doors down for 5 Euros. The storage is in a closet in the back. The door is open with lots of people in and out. There's no record/tag identifying who's bag is whose. I wouldn't leave valuables there.
The only negatives were that there was some mold in the showers and the elevator wasn't working. However, after eating and drinking all day, the stairs were good for us.