The location cannot be beat - you are in the center of the city close to some of the most AMAZING sights in Rome - the Pantheon, Trevi fountain, etc.
Lavinia's place is really great, especially considering you are in the center of the eternal city. Its super clean, has all the amenities you would need, close to some really amazing restaurants (definitely go to Mimi e Coco) and close to public transportation (bus is right on the corner and train is about a 10 minute walk). I especially loved the fact that it has a washer - really helped us not to pack so much.
Lavinia is wonderful - check in was a breeze, she allowed us to come early, gave us directions with multiple ways to get to her place (with pricing) and sat with us to tell us all the things around (including a list of gelato places around her)! She is super communicative and was a wonderful host. I would definitely stay there again!
Just note that the shower is tight, but for those of us used to city living, it is normal, especially considering the wonderful and central location.