We stayed a week at Antonio's. It was a great experience.
The department feels recently renewed. Good bed, modern bathroom, complete kitchen, laundry, internet, nothing missing. The best thing is definitely the location, one block away from the Duomo.
Antonio was very kind and gave us very good recommendations about the city. He was flexible and very easy to reach.
If you don't mind going up the stairs two floors every time, and the normal noise (not overwhelming) of being in a centric location, this is the best place to stay in Florence.