Elena was such a kind and wonderful host who accepted me at the last minute (just one day before!). While we only met to transfer the keys, she invited me to feel welcome in her very beautiful apartment. I truly have no complaints about the apartment at all.
In terms of location, it is definitely not in the city center, and the walk from the apartment complex to the nearest metro station is moderately long (around 10 minutes). However, to me it seemed that Cinecittá is a rather safe area, even late at night. While the walking distance was not a problem for me, it might be an issue if you are traveling with people not used to walking or desire the convenience of being in the city center.
The apartment is much closer to Ciampino airport than Fiumicino, but in any case travelling from Fiumicino is straightforward and not expensive at all. I took an airport bus to Termini station and from there it is a straight ride down metro line A. When leaving the station, walk with the emptier side of the road on your right and you will eventually see the American Express building!