how does it deal with complex environements (lots of drives, multiple partitions with installs on them, etc)
this is where grub falls down and the simplicity of lilo makes it still usable.
lilo may not be simple to setup in such a situation, but it's simple enough that it's failures are simple and so you can fairly easily work your way through the issues to get a working system. With Grub it's hard enough to figure out what grub is really having problems with (what's it trying to do exactly??) that the result is (on a complex configuration) it crosses over to the unusable category.