Three stars.
Firstly, Mauro and Ennio were lovely hosts, very communicative, and wanted to make the stay as good as possible. The apartment is close to the main train station, which is good, though the neighborhood could be described as "gritty" and some people may feel a little uncomfortable walking alone at night. The apartment is nice and spacious, with two large rooms - two queen beds in each. One of the beds was very comfortable, but the other bed unfortunately was not and gave my brother back pain. The other thing to note is that while some air bnb places feel like the owners live there most of the year, others feel like they are rented out most of the year. This apartment falls into the latter category.