We enjoyed staying at Maria's apartment very much.
Location was perfect. It is on a narrow street, which was pretty quiet at night, and during the day. Just a short walk from Ribeira waterfront, where we spend most evenings. Only 10 min walk to Sao Bento train station. Plenty of restaurants nearby as well.
The apartment was just how it was pictured on the site. Good size bathroom with the great shower. Fully equipped kitchen which we made good use of.
We had excellent communications with Maria, who provided us with clear instructions for self check-in, and additional useful information. Also we were able to check-in earlier which was a big plus, as we had a morning flight, so we didn't have to use luggage storage.
We recommend Maria's apartment to anyone visiting Porto