Sandra is a super nice host, she communicates properly and quickly and even prepared a small welcome treat for us. The apartment is clean and have everything 2 people may need. The bed is comfortable and the big windows give you lots of light and a real urban atmosphere. I just loved it all.
Sandra's apartment has a really good location, too. Because of that, be prepared for the noise coming from the busy streets below. You may need earplugs to have a good sleep but in my opinion this is worth to have such a central location with good bus and train connection and to be walking distance from many attractions of Porto.
Definitely 5 out of 5 for me, I will definitely book it again if we visit Porto once more :)