We had a fantastic stay at Savino's. The apartment is very, very clean, and Savino makes every effort to provide anything you need. We were able to wash our clothes, and he even made us dinner one night! He loves giving recommendations about the city, so be sure to ask him what you should do and where you should go. Unlike most Airbnbs I've stayed in, Savino likes to hang out with his guests and even introduce you to his friends. Likewise there may well be another guest staying at the apartment who you can likely interact with.
The location is great - close enough to city center to walk, but just removed enough that it's quiet. We felt extremely safe in the neighborhood and ate at the local restaurant 3 of our 4 nights there! The pizza is delicious and cheap.
I recommend Savino's place if you are visiting Florence. Great location, good value, and personal recommendations for the beautiful city of Florence.