Very stylish, comfortable and well-designed apt. in a small residential area off the busy street and within close distance to shops, restaurants, and mass transit options (Sao Bento train station, and Batahla bus stop, and the funicular / incline tram to Ribeira area.
The hosts had some thoughtful essentials (salt, oil, vinegar, laundry pods) which were a nice touch. The bedding, AC and appliances were all of high quality. The check-in was very convenient (lockbox) but I would recommend packing light and arriving before it gets dark as you have to traverse a few uneven, cobblestone streets to reach the front door.
Overall, it's a lovely place to base your time in Porto. If this cozy apt had a terrace or balcony, I would give it a 5 star rating.