Pros - Very lovely apartment, great central location, close to many attractions, train station, perfect for a short stay in Florence. Kitchen facilities which are superb, makes things a bit cheaper if you wish as local food shop over the road so could easily cook at home in an evening to keep costs down if you wish. Also means you can buy lunch bits and store them in the fridge.
However, the mattress is quite firm (certainly more than I am used too). It was quite noisy due to eateries close by (therefore not able to open windows) and heavy footed residents. If you are not booking the whole apartment you will most likely have other people staying with you (but the room does lock).
Overall I would recommend as long as you are aware of all the little details. They were very accommodating and did their best to allow us a slightly earlier check in.