Our stay at Pina's place was as expected : very good !
Pina was really fast and efficient to answer my questions before the arrival.
She is a very nice host, she welcomed us in the evening with an "aperitivo" and on the day of departure, her husband Leonardo and son Marco wished us a good trip back home with a breakfast in a pasticceria. Pina is a guide in Roma so she knows what she talks about and gave us good advice.
The access to the historic center is pretty easy by metro. The house is located in a nice neighborhood, in a non-touristic area and the apartment is clean and well-equiped. The only weak point to me would be the wifi that I could barely detect sometimes but Pina works on it. I would definitely recommend that place, just for the "human touch".