Location: perfect. It is in the centre while being very quiet, and feeling like a little oasis from the crowds. I put this first as with a kid, I always worry about noise at night. The flat was very serene.
Host: very friendly and helpful! He gave us some really good recommendations (the bar pasticceria piccioli he recommended for breakfast was our favourite little place, and our toddler loved his food recommendation of a tuscan tomato-bread soup Pappa al Pomodoro. The kid hates soup and tomato but this was such a hit we have already made it at home!)
Flat: lovely, clean, and felt like a very authentic and well kept Florentine flat. Lots of character. It also had everything we needed to make some nice meals, without being cramped as in some airbnbs.
Great location, flat and hosts, I would definitely recommend them to anyone :)