Our family booked this apartment for three nights, but conditions were so poor that we decided to leave after only one. We experienced a variety of issues, including the following major ones:
1) The apartment was full of mosquitoes, covering us with bites and waking us up by stinging our faces in the night. This was partly due to a window having been left open before we arrived, but even after we closed it, the mosquitoes seemed to keep arriving, perhaps because the windows do not shut firmly.
2) Someone entered the apartment without notifying us. The wifi password they had given us initially was incorrect, and after we reported this, they went in while we were out and replaced the sheet it had been written upon.
3) The shower was essentially unusable, very small and spraying water everywhere.
Smaller issues were an overall lack of cleanliness (dirty cushions and couch), impolite communication via text, and their request to take garbage out to an unfamiliar location, with no map provided. (Given that we pay a cleaning fee, should guests be responsible for taking garbage out at all?)
Florence offers lovely places to stay. We deeply regret our booking at Costa di San Giorgio.