My wife and I recently stayed at this very nice place. It is clean, modern, well equipped and on the ground floor. It is centrally located so that many of Rome's finest sites are within walking distance. There are many fine restaurants and other necessities nearby.
Claudio is a great host. He made arrangements for our transportation to and from the apartment. He met us there when we arrived and spent time with us explaining the apartment and the neighborhood. He speaks English quite well. I didn't have any trouble communicating with him.
If we ever decide to return to Rome, we will try to stay at Navona Nice House again. It is in a good location and we felt safe there.