I will start by saying that I noticed that Estela has only received positive reviews in the past - I think that she must have been having an off week when I met her. She definitely seems like a very nice lady, but the three of us who stayed with her found communications with her EXTREMELY confusing. Her English was very limited (she mentioned several times that she was very tired and not feeling well, perhaps this is why she was struggling to find words in English - this happens to me in my 2nd language when I'm exhausted), which meant we were never totally sure if we understood what she meant or if she understood what we were asking her. Additionally, she gave us conflicting information about the cost of extra guests staying in the house (when I messaged her to ask if I could bring another friend, and how much that would cost, she said "don't worry about the price." I took this to mean, the price will remain the same, but when I arrived, she made it clear she wanted more money, but would not specify the amount, and said she would talk to me about it the next day. The next day I still did not get a clear answer about the cost, and I only found out how much she wanted on the day before we left).
I was disappointed in a few other regards as well. #1, when I arrived with my friend, she had put sheets on the two twin beds in the same room, and closed the door to the 2nd bedroom with the double bed. I asked her if I could sleep in there, and she said we are two people and she set up two beds. I insisted (my friend and I had been staying in hostels for over a month and we were looking forward to having some privacy), and when she opened the door to the other bedroom, she had not made the bed and had stored a baby's crib and toys in there. She called to have it removed, but told me it was expensive to do extra laundry and clean the 2nd room. On our 2nd to last day, Estela came by the house with a large bag of clean linens and asked if she could leave it there until the new guests arrived. She set it down in the living room... I thought that was unnecessary - her office is right next door (shared garden with the house) and she could have stored it there instead of us having it in our way.
Overall, it's a lovely house and garden, and it's located in a fairly quiet residential neighbourhood close to a grocery store. If you are looking for a place that's walkable to downtown Porto, this is not the right place for you - taxi or bus is necessary (about 20 min taxi, 30 min bus to downtown).