I'll start with the positive - the location of this apartment is great. You're a short walk from all of the major sites in Florence, and the view is absolutely incredible. We loved sitting outside on the balcony and taking in the view of the Duomo - it is really unmatched. The bedrooms are very comfortable and spacious. There are a lot of stairs, but we knew that when we booked, and it didn't bother us.
The downside was really the shower. The water would get hot for just a moment but switched between hot and cold the whole shower and truly made us dread taking showers there. If you don't mind cold showers, this wouldn't be an issue, but it would be enough of a reason for me to not book this airbnb again.
One other small thing - there were a few things that were not provided that we thought should be such as hand soap in the bathroom and kitchen, dish soap, and enough toilet paper for our week-long booking. We had to buy all of those things ourselves.