Your choice really. They both have nearly the same advantages disadvantages at this point, so it's just a matter of which one you are familiar with, or want to go with. The biggest difference I believe would be:
Grub installs only a portion of itself into the MBR, this is basically a file that says, go look over there, which is pointing to the actual Grub.conf file on the drive. Make for easier updating, no need to remember to install into the MBR each time..
LILO installs into the MBR. To me, that calls for a bit more risk, but has easier syntax (arguably) and has just been what I've been used to using.
As they are both just as capable as the other, in both terms of performance and eye candy addition, it's personal preference really...