the apartment is really well located in the old Florence. you have the main attractions at 5min foot. you also have delicious restaurants near the location (pino's sandwiches is a must).
at night, it's really quite. I was there on a week end, and I didn't hear anything. it was calm.
the flat itself is awesome. you have everything you need, specially the air conditioning. the room is huge as well, it was quite the surprise!
you have supermarkets near as well if you need to.
I would definitely recommend this apartment for your stay.