The apartment is great, quite comfortable, airy, well lighted and with a great location! You can reach any part of the city on foot. I was four days there with my 13 year old daughter and walked from the Palatine to the Vatican and Trinitá del Monti to Trasteve, no need to take any transport.
Jack is very nice and helpful, aswell as Fabio, the neighbor who runs the apartment. Fabio enabled us un early check in, as the arrival time of our plane. He also helped us with booking a taxi to the airport.
The only observation I would make to further enhance this excellent hosting is about the lack of internet connection.
I'm already dreaming of going back to Rome and staying again in this delightful flat.
Many thanks to Jack and Fabio.