We stayed in Firenze for 3 nights. The apartment had a perfect location, witihin walking distance from all the main attractions. Comminication mainly went through her Maria's maitress(as she was out of town), who was very helpful and replied immediately. We arrived by car, and there is plenty of parking spaces just outside the apartment.
The apartment was a bit smaller than it seemed on the pictures, and the cleanliness was not great, and there was a bit of a smell in the apartment(probably because it is an old building). We had to wash some of the glasses before use as they were a bit dirty, and we had to request toilet paper and dish soap from the maitress(whom conveniently lives 10m away), as the apartment did not have any.
All in all: Perfect location to explore Firenze, good communication with friendly host, but not very high standard of the apartment.