Advantages:
Very convenient location; ~1min away from metro and bus that gets you to all Rome attractions. Also on main metro line (A) that connects to Ciampino airport).
Safe area; access is on a main street, well-light throughout the night and with several shops open through day.
Close to cafe, forno and supermarket to get you ready early in the morning.
Close to some great evening places to eat or have a drink, off the tourists honeypots.
Host is (almost) instantly reachable via airbnb messaging, and even cell phone after check-in.
Check-in was via keys locker box + we were able to meet the cleaning person before typical check-in time who allowed us to drop off luggage before the apartment was ready, which was super convenient.
Cleaning person was very polite and did a fine job.
Disadvantages:
This is an apartment in a probably ca. 70s or early 80s building, mixed with offices and homes. The age of the building reflects on the apartment, which is a bit worn out to get 5 star rating, but ok for 4 stars. Yet keep in mind that, though the building is a bit aged, apartment's bathroom is renovated and kitchenette offers an induction stove, microwave oven, adequate pots and cutlery and a (little and rather weak) fridge.
Bed duvet covers were missing, instead a pair of sheets were wrapped around the duvets. If covers were up to towels level, the guests impression would be much improved.