Well I think an earlier manifestation of the Brandenburgs would
be the storm troopers employed by Ludendorff in the 1918 Michaelmas
offence. These are specially trained assault troops organised into
assault companies who are meant to exploit gaps in the enemy lines
and infiltrate as far as possible into the rear of the enemies. It
was the first employment of infiltration in infantry tactics.
In terms of fighting qualities, personally I think
the best German formations inspite of the atrocities commited by
them would be the classical Waffen SS divisions IE Hitlerjugend,
Das Reich, Totemkopf and Leibstandarte Adolf Hitler