We really liked staying at Marco's apartment. He was very quick in communicating and answering questions. The apartment was recently renovated and comfortable for our group of 10 (+2 infants). We loved the style with the retro bikes and scooters.
The apartment is not in a tourist-popular area, and no spectacular views or other. But the area felt safe, there is a nice coffee place around the corner, a bus stop just in front, about 8 minute walk to the nearest subway stop and about 10 minutes walk to the Vatican.