This place has a lot going for it but a few areas that are not ideal, depending on who is looking at booking. We were three travellers: me, my wife, and an 11 month old.
Pros:
Communication with Sabrina is very good
Paolo, who checks you in, is a cool guy, and was easy to communicate with and met us at the apartment.
The location is perfect, in Trastevere in a quieter street, we walked to all major sites, and the best restaurants on your doorstep.
The roof terrace is a great place to chill, or have a dinner/drinks
Cons:
Apartment is small
There is a bright street light right outside the bedroom window, that makes the room bright even with the shutters closed. This may not affect everyone, but our son kept thinking it was morning, and time to wake up! A "blackout" curtain is suggested.
The kitchen seemed understocked - ie there is a holder for kitchen paper, but no kitchen paper, and there is an egg flipper - but no pan. We like to fry eggs in the morning and had to do it in a pot!
The bathroom is incredibly small, if you bend down in the shower to pick up shampoo your back knocks the tap and either changes the temp or turns the shower off.
The cleaning fee that is normally itemised in the Airbnb quote when booking, is not included but paid on arrival (as per the fine print). Be aware of that if you are doing price comparisons with other places.
All in all, even with minor negatives, I'd still recommend this spot.