Less than a 15 minute walk from St Peter's. Apartment is large and well appointed. Might just be a translation issue on the listing, however to clarify so others are not surprised this is not a penthouse apartment as it's not on the top floor of the building. Additionally while you do have a nice view of the basilica it is not via a terrace but a balcony, albeit a large one.
Beds were comfortable and there were plenty of extra linens. Kitchen is large and has everything you need if cooking is something you want to do. There's a decent sized grocery less than a minute from the apartment which was very convenient.
Main bathroom wasn't the cleanest and the shower has a pretty bad leak which has been there long enough to warp the floor boards outside. The shower in the master bedroom also has a broken fixture.
Get the impression the place was really nice a few years ago, but hasn't been kept up by the owners like you would expect of a place advertised as 'luxury'.
It's run by a 3rd party who services multiple airbnb's in Rome. He was excellent and very accommodating. Don't fault him for the issues pointed out above a he can't do much if the owners aren't going to address issues.