We went to Porto for a long weekend and stayed at Marco's studio.
Our stay couldn't have been better! The location is excellent, in the heart of the old town; the studio was exactly as in the pictures and extremely clean - better than a hotel I would say.
We never met Marco himself, only his wife Carla, that was very welcoming and helpful. Also, Marco was very nice and accommodated our request for an extra guest for one night.
Overall it was one of our best airbnb experiences so far! - Highly recommended!