There is really nothing to add to: It is the perfect place to stay when you're in Florence. The apartment is super central, everything is so close by: the sights, supermarkets, garages and the station also isn't far.
The apartment itself is super nice with a balcony, where you can have the typical Italian breakfast that you can get right in the morning from one of the bakeries nearby.
Nadja and Brad have provided everything to make the stay as comfortable and easy as possible.
They tend to your every needs and they are always available for questions or issues that might arise.
I can only recommend a stay with them.