Microsoft has released a full exFAT driver for XP.
If someone has not noticed (search for Habra tells me that it seems to be not yet), Microsoft has released a full exFAT driver for Windows XP .
In addition to the advantages and disadvantages of exFAT, it is worth noting that Microsoft declares improved compatibility of this file system with flash disks due to better placement of service information for this type of media (see the first link at the bottom of the page).