The location is great, close to the Colosseum. Being a subterranean apartment, even on a warm and sunny day, you could feel the dampness, which I guess is to be expected, although I would have been happier without mold in the bathroom. The air conditioner helped a bit with the humidity and was a very appreciated touch. The bed was very comfortable. Most of the furniture is old and the kitchen chairs are not very sturdy, so be careful when you sit!
The place was pretty quiet, because we had fairly respectful "neighbors" (other guests, not sure if those are all Paola's, but the residential building where we were has quite a few rooms/apartments operating as BnBs). I could see how if guests in the adjacent room or upstairs were noisy, it could be a bit of an issue.
The free bottle of Chianti with pasta and sauce was a nice touch, and while breakfast is not included, there are lots of bars nearby and even a Carrefour Express grocery store a few minutes away. While I would recommend staying at Paola's, since the place definitely does have some charm and is in a good location, the mold issues and less-than-sparkling overall cleanliness, might keep me from returning.
On a more positive note, Paola was very quick at responding and even organized a driver pickup at the airport, which was very much appreciated. I didn't get to meet her in person, as a different host greeted us at the property.
Overall I think this is a good place, but could be great with a few simple improvements.