We stayed at Luisa's for 3 nights. The house is very nicely designed (just like the pictures) and in a good location.
When we arrived, Luisa had left a detailed welcome pack, along with some tasty cookies and plenty of coffee - which was a lovely touch.
From the house, it is a 25-30 min walk to the Centre. At the end of the street, there is a stop for the tram which costs €3 per journey. There is also a big super-market nearby.
During our stay, Luisa was always quick to respond, if we had any queries.
Overall, we had a great time staying here! And would definitely recommend it, if you don't want to stay in the centre of Porto.