I did not know that SanDisk’s default was exfat without a partitioning scheme. I’ve gotten flash products of large sizes from several makers that still use older FAT32 as the default. With that said, I’ve seen it most with microSD cards. I always assumed the likely reason was because some accessories still use FAT32, and formatting a FAT32 drive to exfat or NTFS takes seconds without 3rd party software, where was formatting a larger drive to exfat or NTFS to FAT32 is not so simple, even though FAT32 can handle sizes up to several TBs IIRC.
I agree with you regarding both the overhead and compatibility, but I still consider NTFS + GPT as the most reliable option (obviously it’s only useful provided NTFS will work with all items the drive is used with.) Obviously that is my personal opinion, since exfat has certain benefits with flash drives like the less overhead, how the size of a file tends to be slightly smaller on exfat disks, the preservation of write cycles, and slightly better speeds with certain sized files. For me personally, NTFS became a more viable option upon learning how to enable NTFS write support on OS X for the rare times I need to write to a NTFS disk/drive on OS X.
