I spent two weeks in Celementina's apartment and loved my time there. I should preface that I was born and raised in Florence, so I am not easily impressed by the local attractions, although the apartment is right in the heart of all things Florence (right near Via Tornabuoni, and a block from Ponte Vecchio). So when I rate the apartment and its location, I am doing so with a local eye. The place is simply amazing - it has an ample living space, which I used to eat, relax, and work remotely many hours each day. The master suite is ultra quiet and comfortable, with a lovely en suite bathroom. The kitchen is functional and well equipped. A lovely interior courtyard with old growth trees provides quiet respite - although it is in the center, the place is dead quiet - great sleeping.
Having spent two weeks in town visiting with folks, I had to use the washing machine, which is perfect, as are all other appliances. Clementina is a lovely and experienced host, and you will find dealing with her to be a very smooth experience.
Lastly, on the value rating - while this is not the cheapest location you will find in and around the Florence city center, believe when I tell you you will not find another one like it. Having lived in Florence for many years, I can vouch that this is not your typical central apartment - even when you strip out such niceties as cotto floors, 20-ft ceilings, and 14th century wood beams.