Upgrade to Jessie - grub-legacy vs grub2; GPT partitions

[Robert S <robert.spam.me.senseless@gmail.com>]

Hi.

We recently had a hard drive crash on our machine which has been
running debian for many years and has been incrementally upgraded.  We
use it for a small business.  I have not yet upgraded to debian 8.0.
We plan to transfer our backup to a low-spec machine (Gigabyte Brix
with 120G SSD) then do the upgrade.

I note that the bootloader debian 7 has recently been upgraded to
grub2.  This seems to be considerably less transparent than
grub-legacy.  Also - should I use GPT for our new partitions?  This
seems to require a small partition at the beginning of the disk, but
does not require extended partitions and is more flexible in terms of
resizing partitions.

My questions are - should I use grub-legacy (which seems to have all
of our required features) or should I switch to grub2.  Will
grub-legacy eventually be phased out?  Is GPT preferable to the old
partition scheme?

Thanks in advance.