I have booked this airbnb for a few days with a friend and there were many postive things but as well negative ones.
Location: The apartment is not located in the city center but that wasn't a problem to us since the metro stop "Basilica S. Paulo" is just a two minute walk away. It takes you no more than 10 Minutes to get to the Colosseum and maybe 20 to Termini station. All in all, it doesn't take long to get to all the important attractions. If you come from the FCO airport it does take an hour to stop at "Ostiense"train stop and then to take the bus to the airbnb it takes another 20 minutes.
The street the stay is located at is lively, there are a few restaurants around, a good gellato shop at the corner, a tabacco shop for buying tickets and also a grocery shop (coop).
Self check in: you can check in yourself with a key that's located in a combination locked box. The host will send you an instrucution video which is very easy to understand.
Amenities: the kitchen is well stocked and you have everything you need for two people. The bed is what you'd expect from a sofa bed, it's clean and we can't complain. The bathroom is where we have to leave a negative remark. The bathtub and shower is definitely an older model and we have found an excess of mold on the sliding doors when closing the shower and in the corners. Considering that we paid for a cleaning fee it was highly disappointing.
Generally it would have been good value for the money if it wasn't so unclean. You can give the host the benifit of the doubt or not.