We just stayed for three nights in Massimo's apartment near Navona, and it was extremely nice!
Massimo had kindly supplied a very good travel cot for our baby daughter, as well as some Gin for me.
The location is excellent, I found a convenient parking space by the river nearby, you can walk to all the famous sites easily, there are good restaurants in the area.
The apartment is very tastefully furnished, with a large, comfy bed in the main bedroom, shutters on all the windows, good bathroom with decent shower, small but functional kitchen, comfy sofa/bed in the lounge, and large daybed/extra bed in the other room.
We would happily stay there again, next time we come to Rome!
Nick