http://www.strategypage.com/htmw/htsf/articles/20060414.aspx

April 14, 2006:
As good as the U.S. Army Special forces are at training foreign troops, many of these foreign armed forces now prefer U.S. Marines. This began when some U.S. officers, responsible for assisting in the training of military forces in Third World countries, began declining, when offered Special Operations Forces (SOF) personnel.

Publicly, the reasons offered are usually couched in terms that suggest the SOF people are needed elsewhere, which is certainly true, given ongoing operations in Afghanistan, Iraq, and elsewhere. But privately some of the advisory personnel cite the fact that SOF personnel usually bring with them all sorts of specialized equipment that the host country will never be able to afford.

Moreover, the capabilities for which SOF trainers provide training for are often much too sophisticated for local, and usually poorly educated, troops to absorb. An additional objection is that the nature of the way in which SOF operates is just too "undisciplined" for Third World forces. Apparently when asked, experienced advisors will ask for American Marines rather than Special Forces. The Marines have been helping out with the foreign troops training since the war on terror began and the more basic and down-to-earth approach of the Marines has been more attractive to many nations.

The SOF are still very good at organizing and training irregulars. But when it comes to turning a bunch of civilians into disciplined troops, the Marines have an edge.