We stayed at David's apartment for over a week. It is located one block away from the bridge, Ponte alle Grazie (2 minute walk). We were concerned with the check-in from a previous review but we didn't have major any issues. David has a company that runs a bunch of apartments and uses an employee to open the door for us.
The apartment is L shaped with the living room facing the street (on the 2nd floor (1 in Italy) so you need to walk up 2 flights of stairs. The bedrooms are facing inside the courtyard, but you can still hear cars and/people if you are sensitive to noise. Our only complaint was that the bed mattresses in both rooms were a little too soft (felt like a cheap Ikea mattress).
There is a taxi stand appx 3 blocks north of the apartment (5 min walk). Taxi's are reasonably priced for the city and they can drive within the ZTL.
We came in January so Florence was pretty quiet. We were really happy with the location as it was away from the main tourist area but was still close enough to everything. Suggestion: do your own research and don't visit the recommended restaurants on the hand out that is made by David's company as they might be tourist traps. We went to one that was recommended on the list/map: La Buchetta and felt the quality was pretty bad (we visit Italy often) and every single guest in there spoke English (we typically like to go where locals go). Go give 4 Leoni and Il Guscio a try.
Overall, we were happy with this AirBnB and would recommend this apartment for people with a small family or people that want a location that is relatively quiet and away from the crowds.