The flat and its location are amazing. I think this is the best place to stay when you want to visit Porto. You have an astonishing view from the window straight onto the ocean. There are many shops and the best seafood restaurants in the whole city nearby.
The only problem was a construction site erected on the building. Workers were standing on my balcony each morning (which the offer description didn't mention). Better ask if they are still around when you'll be renting the flat.
Other than that, the flat was clean and sun-lit from morning till night.
Highly recommended!