I use grub legacy (0.94 as it happens - I'm avoiding 0.95 for now) without issue.
I installed Slack yesterday for the first time on a triple boot laptop (XP, Gentoo and Slack). No lilo on the Slack install obviously.

My grub boot-loader is from my Gentoo system - even without Reiser in my Gentoo system I was able to add Slack (reasonably) easily.
I like the option of being able to alter the boot menu at the menu with grub. Allows you to test things, and get it right without having to constantly fiddle with "reboot/update conf/reboot ..." cycles.
Maybe you can also do this with lilo - been too long since I tried it.

I believe you shouldn't have any issues managing any O/S with grub. These days I always recommend putting it in the MBR.
Fresh Windows installs will always over-write the MBR, but re-installing grub is pretty painless.
Well, it is for a Gentoo user