Great place to stay. Giuseppina is a wonderful and welcoming host. I spent 2 weeks at her flat. It was clean, quiet, and with everything you need even for a longer stay. It is literally 1 min from the metro A which takes you to the Vatican City and to the south of Rome (besides of course Termini). Not being in the centre, it takes only 25/30 min by taxi to reach it from Fiumicino's airport.
The area is well served, with supermarkets 5 min walking distance, and bar with great coffee and croissants. If you find this free, do not hesitate to book.