My experience in Robert's airbnb was really great. The apartment is clean, the kitchen is equipped with all the amenities you need for a short stay and the double bed was very comfortable. Just beware of the ceiling. I knocked my head really hard a couple of times (hahaha). Would definitely book it again. The place is near to all the main attractions in Florence + there are good supermarket choices around the block.
Also, the building was silent most of the days, but if you're a light sleeper, the noise from some guests of the other Airbnb can be a little annoying. Not problematic, though.
Great choice to stay in Florence! (The proximity to SMN station was also a plus!).