I am almost tempted not to write, because if too many people would know how wonderful this place is, it would be impossible to reserve in the future.
The views are even better as in the photos, and the apartment feels like home from the first moment...Vivian's attention to detail is impressive. In the morning one can hear the voices of women working in a nearby kitchen, in the evening the nuns pray and sing softly. It is Italy the way you've dreamed of it.
We were there in the high season, and something was always going on evenings in the piazza below. There are nice beaches in Terracina, but with a car we could also explore Sabaudia and Sperlonga as well as make sightseeing trips to Rome and the Naples area (Vesuvius, Pompeii, Capri, etc.)
The only caution is that the views come at a price. People with mobility problems might be better off elsewhere since the historical center is all stairs. If you are not fit when you arrive, you will be when you leave.
We are already thinking about our next trip. We already know where we want to stay.