I stayed at Joana's place with my boyfriend for three nights.
Her place is very conveniently located in the centre of Porto: you can walk to all major tourist attractions and can easily access it via metro from the airport.
The flat was very clean and contained all essential amenities. Joana's mum welcomed us to Porto, showed us the flat and provided us with useful tips when we checked in.
Throughout the trip, we were able to communicate swiftly and efficiently with the host and we were also able to leave out luggage after check out as our flight was late at night.
Overall, I would recommend Joana's flat to anyone!