I travelled to Florence with my cousin & we both loved staying at Francesca's apartment! The location was amazing. It's about 50 yards from the Duomo so it's always easy to get back home. It's a good walking distance from everything else you'll want to see in Florence.
Franci met us at the apartment when we arrived and was really helpful in getting us settled in. Her guidebook on Airbnb was also a big help in picking out places to eat, see, etc. She printed a copy of this and had it waiting for us when we arrived, too.
Being so close to the Duomo, you'll definitely hear the bells in the morning. It wasn't a big deal to either of us, but just a heads up.