The first Linux I installed (that was back to 2003) defaulted to GRUB as
bootloader and GRUB (legacy) is the only bootloader I've installed -and
tweaked- since then. While I've seen "LILOs" when testing another
distributions, true is that I have not a deep knowdledge of how it works.
But, for what I've read, LILO is still requested for some complex booting
environments where GRUB has some difficulty and OTOH, I think is a very
good approach to keep the two most used bootloaders in a good shape.
Greetings,