We had a nice time at Nuno's apartment. All in all a good apartment for a short stay for a couple/a single person.
Pros: the large balcony, modern clean bathroom with a good shower, Nuno was very accommodating, fully equipped kitchen, good wifi.
Cons: the location is a bit further out of central Porto (perhaps a 30min walk to the toursity stuff) so not ideal if you want to explore by foot. That being said the metro is 10 mins away.