My friends and I stayed at Casa das Virtudes and we loved it. The house is in the absolute perfect position to explore the city, near the center and everything you need. The apartment itself is very comfortable and lovely decorated. It's exactly as depicted if not even better.
We never met Miguel, the owner, but he was very helpful and easy to talk to as much as the lady who lives at the ground floor. She only speaks portuguese but is very very kind and helpful too.
We definitely reccomend this house for your stay in Porto and we would be pleased to come back there!