We had a great stay. Arianna responded very swiftly to all communication and made arrangements for a perfectly smooth check in. Very much appreciated after our flight was delayed so we arrived rather late.
The apartment is as described; actually the bedrooms and kitchen are more spacious than they appear in the photos. It is super convenient for visiting the Vatican museums and we mostly walked to other sights, but metro, bus and scooters also easily available for more distant sights.
There's a panini place open late, on the corner of the street, turn right out of the apartment, corner of the piazza, it is small but does a huge range of fillings; all we tried were excellent.
As Arianna says, the dining/social area in the apartment is rather small, but the rest is spacious, and I guess most visitors will be out most of the time.
Highly recommended.