I stayed at the Residenza Matteucci for 2 weeks in August 2016 and it was a wonderful experience. Barbara, the owner, and Angela, her mother are great hosts who think of every need that the guest may have.
The location is super convenient less than 5 minutes walk to the metro and to the train station that goes straight to the airport. It is also very close to the station that takes you to the sea. Also within 5 minutes is EATALY, the mecca for food eating and shopping. If one likes to go out dancing, the B&B is conveniently located between two great night spots (Testaccio and Garbatella). Also, don't miss the great ice cream at La Romana just across the street. Enjoy your stay!