Pros:
1. The location. Everything what you most probably want to see in Florence is within ~10 minutes walking distance. And just around the corner will be a super nice street with restaurants, cafeterias, gelaterias etc
2. The staff are friendly and helpful, and the room was kept clean. But to be honest, the 4 star rating on their site is a bit overestimated.
BUT, the location from the sightseeing perspective is very very good and you will find the staff friendly and helpful.
Cons:
1. The hotel is noisy. Because of the location, there are a lot of people wondering around the alley - all night. The soundproofing of the room - at least on the alley side of the hotel where we had our room - was, well, there was none. So the sleeping will be struggle. Please ask room from the other side of hotel, not on the alley side, because there won't anything to see from the window anyway.
2. Breakfast. It is below average and if you are staying more that 1-2 nights, it will start to push back. But, as said earlier, there will be tons of cafes etc. within 100 meters and you will find really tasteful breakfast from there with quite a decent price.