Very good spot. Incredibly well located, in the heart of Porto. We were received by Sonia's friend Bino and he did a very good job at accommodating us and letting us know of the city's hot spots. The place looks like a hotel room; very clean and spacious. Internet worked well, bed was comfortable and the bathroom was great as well. Two A/Cs : one in the bedroom and one in the living room.
Be warned thought that it can be quite noisy at night, especially if you are sleeping in the living room. Other than that, I definitely recommend Sonia's place!