Every U.S. soldier deployed to a combat area is issued C-A-Tourniquets. If you google the clinical research done by the U.S. Army, you'll find a number of tourniquet myths debunked and they have been credited with saving over 1,000 lives. The military has taken a more liberal approach to the use of tourniquets because of the clinical studies and results. The company I work for manufactures the C-A-Tourniquet shown in this thread. We also make a bright orange tourniquet for EMS use. It is crucial to note the time of application on the tab provided and always look for a tourniquet on incoming patients.
Here is a good case study/discussion in EMS world: http://emsworld.epubxp.com/issue/39236/31