Lucia's is a great flat and is illustrated accurately on the website. It is about a 10 minute walk to the main tourist areas so the location is ideal. There are plenty of shops and food places nearby, and the flat feels perfectly safe. Lucia was a great host and gave really clear instructions about check in/flat issues and the apartment was really comfortable.
I would happily recommend staying at Lucia's - if I was to visit Florence again I would stay here.