I stayed here with 5 friends for 9 nights over the NOS Primavera Festival.
Miguel's place was perfect for our needs and Miguel himself was very friendly and accomodating, even creating a personalised PDF of recommendations for our visit, including restaurants, cafes, nightlife and cultural spots.
Whilst the apartment is not in Porto (located in the city of Gaia across the river), it was only a short metro ride of 10 minutes to reach the main city centre and the surrounding attractions.
We would recommend Miguel's place to anyone thinking about staying in Porto/Gaia.