I should start by saying that the apartment itself is fantastic. It's in a great location and is an easy walk both to cool local neighborhoods and to many of the primary tourist sights like the Vatican, Pantheon, and Piazza Navona (to name just a few). Also, the apartment is charming.
The real issue was, first, that upon arrival, there had been some mixup with the cleaner, so after 20 hours of travel I arrived at the apartment and was told it wasn't ready and I should leave my bag and wander. This was pretty much the last thing I wanted to hear after not sleeping for more than 20 hours. Also, it was a very unnerving start.
Fast forward two days to when my boyfriend arrived. When he came to the apartment, there suddenly wasn't running water. Again, not the host's fault, but the water outage lasted for 24 hours. We were literally "showering" with washcloths.
Finally, the apartment lacked some basic necessities, like hand soap and shampoo, despite advertising otherwise.
All of these frustrations were made worse by the fact that there was no real effort to compensate us for the massive inconvenience of (most importantly) no running water. Although Carmela at one point mentioned she would get us a bottle of wine as an apology for the mishaps and thank you for our patience, it never materialized.
Upshot is: great apartment in an awesome location, but probably the most frustrating stay I've ever had at an Airbnb.