Nice flat, well equipped, clean, easy to access, close to Trindade metro station, to small supermarkets and to the centre of Porto, and as well to several good and cheap restaurants.
Be careful if you are averse to noise. The building next door is under renovation (full with crane as a view from balcony) and they start work (including heavy drilling) before 8am and until after 6pm.
During the day, you can set foot in the flat only with good ear plugs otherwise it is unbearable.