Pros: Location is excellent. You probably can't find a more centrally located place for the price range. If you are staying for a couple nights in Florence and want to see all the sights and are just looking for a place to sleep this is a very good place. Also, the host is very responsive.
Cons: The apartment is a very small studio. If you are looking for a long-term stay, I wouldn't recommend it because it will feel cramped. The building is old and the walls are very thin and you can hear the neighbors. Fortunately, the neighbors were generally quiet, but you will hear them come and go in the night/morning.