We stayed for four months, and the appartment entirely met our expectations. An old house recently refurbished by its proprietor, it is very nice, with a personal touch, and extremely well located. Via del Canneto is very quiet (no cars, hardly any traffic) but no more than two minutes away from Ponte Vecchio.
The apartment is not very much exposed to the sun; we stayed there in summer and were very glad it wouldn't heat up too much (often a big issue in Florence, which tends to be a hot and humid place).
We found the proprietor extremely helpful and friendly, very efficient and reliable. He provided us with an additional baby's bed at no cost. When our baby was ill, he helped us find medical assistance, and we could also draw upon his help for minor issues. At the same time, he is very discreet.
The price of the apartment is not exactly cheap, but friends who live in Florence constantly pay only little less for comparable places, and the service provided was impeccable. We would certainly come back.