The hosts, Stella and Camilla, were welcoming and communicative throughout the process. When there was a slight issue with the bathroom and a question about the working of the stove, they took care of it right away. Stella provided us with great suggestions of where to go and what to see. The apartment was comfortable, sleeps up to six, and the dining table was large enough to accommodate all - which is actually quite rare from my experiences with AirBnB accommodations in Italy.
We had two issues however. The apartment, 2 miles from the Vatican (that's a 40 minute walk), was not nearly as central/accessible as described. There are bus stops nearby, but the frequency varied. The metro stop is 10 - 12 minutes walk away. It took about 40 to 60 minutes (each way) to get anywhere meaningful in Rome, which threw off our plans to spend the morning sightseeing, resting in the early afternoon, and then going out in the evening. If we had tried to do that, we would have spent 2.5 - 4 hours a day just commuting to and from the sights in Rome. We made it work by staying out most of the day and by using taxis at the end of a long day, but that increased our cost as well.
Also, the apartment is equipped with a tub that is set up for baths, not showers. The shower attachment is set too low (about waist-level), forcing us to crouch in the tub if we wanted to use the shower hands-free to wash our hair. We managed, but this would have been a problem for older people or any one with mobility issues.