The SS soldiers and officers are more aggressive and slightly tougher than their Wehrmacht counterparts with 20 health points and wield more firepower by using the MP 43, while Wehrmacht soldiers are mostly equipped with a MP 40 or Kar98. Like their weaker counterparts, they are encountered in the greatest numbers, and will use that to their advantage. They will stick to machine gun nests, and when B.J kills the one manning it, another will move in his place.
See: Wolfenstein (2009)