Location, location, location. Ricardo's apartment is one of two he has on Airbnb specifically for Airbnb. Located up two flights of stairs with no lift, it is walking distance from the S.M. Novella, Central Market, Duomo, Uffizi, and Accademia.
Clean, spacious, with a jacuzzi in one of the two bathrooms, it's just as good if not better than any Florence Hotel.
There is a washer, but it was on the fritz at the time of our stay. There's a laundromat with dryer though down the street.
There is wifi, but it doesn't work well in the bedrooms, only the living room.
With these things fixed, you couldn't ask for a better stay.