Their flat was very nice and we enjoyed our stay so much.It is very near to train station and the station is just 2 stations from termini.They have around 5 rooms on the flat, but with 2 bathrooms it won't be busy.And also becoz of thick wall, we don't hear any sound from next rooms. We stayed here in winter, but the room has good heater and we didn't feel cold at all.
We forgot to pay city tax when we checked out, but we call then and Paul came to termini station and pick it up which was very helpful for us;)
Definitely will come back when we come to Rome again.