A quick answer is this: Grub.conf is actually a configuration file for the GRUB. (GRand Unified Bootloader) and LILO is LInux Loader.
However, the differences between the GRUB and LILO are mostly from a technical standpoint. As far as the end user is concerned I believe one of the main differences GRUB’s ability to have a background splash screen versus LILO’s white-on-black.
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