I stayed for 10 days in Francesco's apartment, and had a lovely time.
The apartment is located in a residential area, so is quiet at night, add to that a very comfortable bed, and you should sleep well.
It is 10-15min walk to the Metro, 10min to a Conrad supermarket, and there are lots of cafe's and eateries nearby, although you are spoilt for choice in Rome!
I found it very central as well to get around, it is a 10min walk to the Colosseum, so an easy walk into that side of town.
The apartment building and the apartment itself is a real taste of living in Rome, wooden floors, high ceilings and furnished with lovely old furniture pieces. It is on the 4th floor, with a lift, but an old one, so one person and their bags at a time!
If you want a modern, slick, impersonal space, this is not the apartment for you, but if you want a real, homely spot, that gives you a "real" experience of local living, then book it.
Added to its great location (I was also a solo female traveler, and never felt unsafe in the area) , the communication from Francesco and Raffaella before and during my stay was excellent.
A lot has been said about Francesco's kindness, from coffee when you arrive, and any advice on the city should you need it - it is not exaggerated, he is a very nice man! There was also a welcome panettone, and some fruit, which was delicious and appreciated.