I had a nice stay in Claudia’s apartment. It’s very central, 3 min away from São Bento Train Station walking. The apartment is small, but very cozy, with all the important stuff. Plenty of restaurants nearby and Porto is not that big, and you can walk pretty much everywhere in the downtown. Communication was easy and fast. Very strict check-out time it seemed, but it wasn't a problem for me. And Porto is always a great city to visit ;)