The apartment is really great - it is cosy, clean, very well equipped and in a good location - the famous Belem tower and Jeronimos monastery are just behind the corner. It is also well connected with the city center by the public transport.
The host was very welcoming and helpful - after staying there for a week, we had an emergency of flights getting delayed for another night and we were allowed to stay one more night even though the next day new guests were coming.
And finally, thanks for the nice Porto!!