Who is better the british sas or American usmc?

Both the SAS (Special Air Service) and Royal Marines are very lethal parts of the British military, but both have different missions. The Royal Marines are part of the Royal Navy, and operate both as commandos, in small units, or in larger units as part of an amphibious force. The SAS is trained to operate in 2-3's, scouting far into enemy territory. In the 1991 Gulf War, for example, SAS in specially-equipped long-range jeeps roamed the Iraqi deserts from Jordan to look for the Iraqi Scud missile launchers targeting Israel and Coalition troops.