Interesting question. I read some time ago that the U.S. Marine Corps is the world's only service-wide force to be considered elite. Don't know if that holds today.
I have the book below on my shelves, thought maybe a few of you reading this thread might be interested in a bit of information from it.
--------------------------------------------------------------------------------------
"Military Elites – Special Fighting Units in the Modern World" by Roger A. Beaumont
Book jacket copy:
Merrill's Marauder. Darby's Rangers. The French Foreign Legion. The Green Berets. The Commandos. Names that have come to epitomize daring, determination and expertise. Names that stir us with the promise of martial glory. Precisely as they were meant to do. For it is the opinion of the author that many elite military units were formed to serve psychological rather than tactical needs. This book tells the history of more than 80 such organizations, from the Arab Legion of Glubb Pasha to the heliborne air cavalry of Vietnam.
Some elite units, such as the U.S. Army Tank Destroyer Corps of World War II, were created to compensate for technological deficiencies, making up by sheer quality of fighting spirit for the superior weaponry (in this case the Wehrmacht's heavy tanks) that the enemy possessed.
Other units, such as the British Long Range Desert Group in North Africa, or Merrill's Marauders, who fought the Japanese in Burma, were an attempt to compensate for strategic weaknesses. Some, like the Chasseurs Alpins and the Submarine Command, fought highly specialized forms of warfare. Others, like the Waffen SS or the Palestinian Al Fatah, were political groups, embodying as an element of their esprit an approved or respected political attitude.
Some became elite units by association with the tactical success of the weapons systems they operated. This was the case with the German Panzer Korps, and it is now the case with our own Strategic Air and Missile Commands. A few groups earned an elite status by virtue of the military genius of the leaders. So it was with the Afrika Korps under General Erwin Rommel.
Many groups, however, stood for important ideals: the Arab Legion was an example of discipline, the Irgun of resolve, the American airborne divisions of toughness, the Rangers of bravery, the British Commandos of cunning, Special Forces (the Green Berets) of ingenuity, the Japanese kamikaze pilots of ulitmate devotion.
Some succeeded in their psychological role while failing at the military assignment. Many fought brilliantly but were of little final tactical value. Others were capable of a high degree of success but were employed in the wrong role. The U.S. Army Special Forces, for example, were trained to organize and to fight guerrilla warfare in a hostile environment, but instead were used in Vietnam in a counterguerrilla role, as "superior" conventional troops in a friendly environment – with disastrous results.
All these and many more units are discussed in a book which draws on official sources and historical archives throughout the world. A generous selection of photographs, most of them hitherto unavailable, is included.
Roger A. Beaumont, a graduate of the University of Wisconsin, holds a Ph.D. in military history from Kansas State University and was a senior staff member of the Center for Advanced Study in Organization Science at Wisconsin. He is now an Associate Professsor of History at Texas A&M University. Having served two tours of active duty as an army officer, he has written for such publications as Military Affairs, Army, Military Review, Horizon, and The New York Times. . . .
--------------------------------------------
Talk about comparing apples to oranges. For myself, I would not argue that one elite force was superior to another even should I possess particular knowledge about the topic. Far, far too many variables to make elite-to-elite comparisons, imho.
