According to Ralf Mardorf:
I'm still using grub legacy on my machine. Is there a reason not to use grub legacy anymore? I also used grub2, but I don't like it. I never used any other bootloader on a PC. I never noticed any drawbacks using grub legacy. If you are planning to keep your bootloader installation the same, and if you don't plan to change your disk configuration or /boot filesystem, grub legacy should meet your needs with no problems at all. You already have what you need, it just isn't being updated in the repos.
The reasons for using syslinux or grub2 include better support for /boot filesystems including btrfs as well as GPT and EFI support. If these or other features don't matter to you, you can certainly continue using grub legacy until or unless they do. Hope this helps. ~Kyle