A wonderful and convenient place to stay! Everything is within 5-20 min walk and the apartment is very cozy. It is also stocked with sightseeing tips, Italian dictionaries, snacks, etc. AC is a great plus considering I went during the hottest time of the year (August). Alessandro is very responsive as well and will get problems fixed promptly; hot water broke while I was there but he sent a technician to fix it the next day.
Only thing to note, it is on the third floor from US perspective (bottom floor is counted as 0th floor). Please be aware if you are planning to bring lots of luggage! I only had two bags with me and it was no problem.
All in all, highly recommend if you want to be in the heart of Florence with everything within walking distance. :)