We had a great time at João's place. He can be described as a very hostile person who gave us a great introduction to the city of Porto after arrival, and kept in close contact during our stay if everything was ok.
The apartment itself was perfect. It's location in the middle of the old town is perfect, with everything in walking distance. Furthermore it is quite spacious, and nicely furnished. It is a great place to discover the city of Porto, and feel at home right away.