We stayed 7 days in Casa Frederico. Roberto welcomed us at the apartment, gave a little tour and provided all the information that we needed for a comfortable stay.
The apartment was just perfect and very clean. The air conditionig was a big plus, because it was very hot during our stay. The bathroom is big and had a nice shower. The bed was very comfortable. The kitchen area is a little small, but had everything we needed.
The best part of the apartment is the outside area. It was really nice to be able to have breakfast and dinner outside in the shade, under the patio.
As described the apartment is a little bit outside of the city center. The neighborhood felt very safe and you can live between the local people. A bakery and supermarket are just around the corner.
The bus stop is just a 2 minute walk away, with the 49 line you're within 15 minutes at the Vatican. The metro station (Line A, Aurelia) is a 10 minute walk from the apartment.

We highly recommend Roberto's apartment for your stay in Rome!