I've just come back from a lovely long weekend in Porto with two friends. I would recommend Hermino's apartment. There was ample room in the apartment for us and the kitchen was well equipped. Having Netflix was a nice addition when we fancied a night in and the custard tarts and port on arrival was very welcome. The flat is in a quaint residential area within easy walking distance from all the main sites and with plenty of restaurants, bars and a supermarket very near by.