My experience in Joao's apartment was great.
The apartment was very cozy and clean, useful as a base for visiting the city, very near to Apollonia station, so very near to the metro, but at the same time not that far from the center by feet.
And I can even say that Joao behaved in a very good way. When we meet to enter the apartment he gave me some suggestions and brought me in the center with his car. Very kind of him.
If you need to visit Lisbon, i strongly recommend him.