We enjoyed a wonderful stay. The apartment is in a perfect location and provided a restful break from sightseeing, dining and drinking. Marcello, Matteo's brother was extremely helpful with local restaurant recommendations and even printed my parents' boarding passes and booked a (very affordable) taxi to FCO. The a/c works well and the large windows work even better. Wifi is super fast.
One word of caution: the 52 marble stairs leading to the apartment are a killer. I wouldn't recommend the place to people with bad knees.