Stayed for 10 nice, warm but not too hot Tuscan autumn days. Wouldn't have a problem to stay for another week or two in the excellent Carla's apartment. Carla is very nice to deal with, and she keeps the apartment very well organised, all everyday things are just where one expects them to be. Remembering how we lived without microwaves 20 or 30 years ago was actually a bit of fun. Having a look at other reviews is definitely recommended, that will give a pretty complete picture of what to expect.
One thing to mention and quite possibly enjoy is that this part of the old Florence centre is full of night life in the second half of the week, so don't be surprised by a live saxophone solo after midnight or a decent salsa performance between 1 and 2 am. Repair works on the square are still going, but the site is completely dead outside of the normal business hours.