The key to this apartment is location - it's about 25 metres to the Piazza del Duomo. This means it's perfect for sightseeing and using as a base during the day - so you can get up early and buy tickets / see sights / beat the queues, and then still pop back home for coffee and breakfast, or have lunch at the apartment etc (or have a quick siesta).
The amenities in the apartment are fine - not outstanding but perfectly adequate.
The only downside is that because it is so central it can be noisy over night. The main bedroom faces out towards the street and so is noisy - the smaller twin room at the back (where we put the kids) is quiet.
Hot water a bit dodgy! But manageable. Overall it's a great place to base yourself for a Florence sightseeing trip!