We stayed at Maria's place with our baby for 3 nights during a really hot August. We found the place very clean and exactly as advertised. Maria was very quick and helpful with our questions and were very gracious.
The apartment as others have said is about a 30 minutes bus and tram ride to Central Florence.
Having air conditioning really made our stay comfortable because it was very hot, even at night.
The apartment had everything needed to cook, the bed was very comfortable and Maria had a baby cot for us to use, which was a nice touch. Having secure and easy parking spot on their property was really really good.
I would definitely recommend Maria's place for anyone wanting to visit Florence in a car and avoiding the ZTL tickets.