I was reading in my history textbook about the German invasion of British occupied Egypt.
It seems it was like a tug of war... the UK was very successful pushing the Germans out until Hitler (from my textbook:) "sends a crack German tank force, the Afrika Korps."
Yet again another tug of war... finally ending in German victory and the renown of General Erwin Rommel being nicknamed the "Desert Fox".

What was so "crack" about this German Panzer Force? Was it the heavily armored tanks such as the Panther and Tigers? Were the crew trained exceptionally better than others?