At one point or another, military enthusiasts ask this question. Typically in relation to discussions that dwell on the ascendancy of one special unit versus another. "Who is more elite?" When faced with such queries, professional often point out there each special unit is trained for a specific task and require individuals suited for such tasks. That does not inherently make them better than anyone else.
To put things in perspective, the author put together the following summary to differentiate between the units that were frequently the object of the "Who is the most badass?" inquiry. Pros on the forum reviewed this summary favorably, and has since been treated as a reference thread.
Special Forces - force multipliers; unconventional warfare experts as MikeLogics pointed out. Their job is to win over the local populace to the government's side and to organize/lead them against the enemies of the state. This is the reason why CAFGU organization was originally their domain (and remains so to a certain extent). Their arsenal is not limited to their weapons, but include their smiles and personality. (There's a reason why a lot of times they're the ones manning the exhibits during Philippine Army day)
Based on the "A" in their acronym [SFRA], they have a thing about jumping out of aircraft that are working just fine.
Scout Rangers - tip of the spear. COIN is about offering the choice between the carrot and the stick. The rangers are the stick. Whereas SF and SOT teams mingle with the population, Rangers avoid contact to keep the enemy guessing about their whereabouts. (This, according to Victor Corpuz, is the reason why Ranger-only operations don't work -- you need an SF/SOT component)
Force Recon - vanguard of the MBLTs. The PMC reportedly doesn't really consider Force Recon an elite unit. Since PMC doctrine emphasizes combined arms tactics, all units are part of a whole and just have different jobs. Force Recon's job is harder than of other units since they're the ones who are supposed to find / make first contact with the enemy, and consequently fire the first shots.
NAVSOG/SWAG - just add water. When you need an offensive punch from the sea, short of a full-scale amphib operation, these guys are it. (No idea if there are any doctrinal limits to how far in-land they can be used). Armed seaborne operations, such as underwater demolition and hostile-boat boarding are part of the menu.