TBH I've only used it for Hackintoshes and BSDs. I don't know why you'd want it.
But I am finding this hard to post on account of this big hairy grey thing with a long prehensile nose that's in the way...
They only work on UEFI. I don't like UEFI. I have kit in near-daily use that doesn't have UEFI at all.
GRUB works on BIOS, UEFI, x86, Arm, whatever. It boots Linux, all the BSDs, Haiku, whatever. So GRUB wins.
I hate GRUB for its hostility and unfriendliness and impenetrability... But it does the job on more kit than, well, any of the alternatives.