Wish this were a park! Instead, it's a big parking lot on a hill, with a big copy of the statue of David, an expansive view of the city, and some venders of fast food and sovenirs. The parking lot will be packed with cars and buses. If it's cold in town, it will be windier and colder on the hill. I gave it three stars because of the view and the access to the church farther up the hill.
Bus 13 leaves from the train station and goes clockwise around town, over a bridge, and up to Piazzale Michelangelo before coming back down, going over a different bridge, and returning to the train station. It's a free sightseeing ride if you have the Firenze Card!