I've stayed at dozens of AirBnBs in the last 7 years. This is easily one of the best ones I've ever stayed at. It's a beautiful apartment in the touristic center of Porto.
But the best was Claudia & Mário. They were amazing hosts that welcomed us with a gift. They happily shared their local knowledge of Porto, gave great recommendations, and were kind and tried to accommodate our needs as best they could during our stay.
Highly recommend staying with them if you have the chance.