I do find it curious that we describe an entire group of people as one way or another based upon training, service, or other aspect.
US Marine is one way or German KSK (Kommando Spezialkräfte) are another.
A person is a person, pretty much across the board.
When you speak of the average special forces type...let us say 24yrs old, 5'11", 180lbs...runs 3-5 miles 3-5 times a week, swims miles upon miles every week, scuba dives, jumps out of planes, shoots guns, boxes/wrestles/grapples/etc., studies tactics, works on troop movements, etc...within reason, an individual is just that, an individual.
Now if we are considering a 7' 300lb type compared to a 5'5" 130lb type, well that is a different story.
I served 21yrs between US Marine Corps, US Coast Guard, and US Homeland Def Anti-terrorism...I was on the force recon tract in the Marines but a knee injury from a repelling accident kept me out of the jump program...but I went on to be a rescue diver and rescue tower climber...worked with US Marine Force Recon, Navy Seals, Army Airborne 3rd Group, and Delta Force...mostly for cross training and field exercises.
There are exceptional individuals everywhere...the more specific and demanding a group's mission then the more likely the chance for these exceptional types to be grouped together.
200,000+ active duty US Marines...all shoot well, very well...vast majority are in shape, most in very good shape...and are well trained, disciplined, etc.
Of these within this fairly small organization we find a niche of special operations, Force Recon or Recon...with 400-500 members.
These 400-500 are some of the best that the already demanding standard that is required just to be a Marine...so the chances are that the best of the best of the US Marine Corps will have spent some time in Force Recon or the Drill Field (boot camp drill instructors) or both.
Within the 400-500, there are exceptional people...the same is true of any service, special forces or not.
When you specialize the training and the focus then you will get a specific creature, regardless of country or name.
*****
Beyond any internet hero stories, I would say it is the mentality and purpose of the training that will determine a higher level of combat effectiveness.
Those trained to search and rescue will not be trained the same way as a counter terrorism team would be.
Like comparing apples, oranges, and pickled herring.
*****
As far numbers go, one would could infer that a country with huge numbers of people within the military, vast resources, and willingness to commit to military action will have the better potential of large groups of well trained bad-ass types.
But that does not mean that tiny Liechtenstein could not produce the baddest guy on the planet...people are people after all, we mostly fall within a certain range of raw potential.
But the larger countries will tend to have the more well known and within reason the more effective units of exceptional individuals.
A fair amount of consideration goes to location...the extremes will draw out the strengths and weaknesses quickly...be it arctic or arid.
*****
I have a pretty strong background in actual combat training.
With extensive close combat, small arms combat, and infantry support with mortars.
I taught combat knife fighting at ITS (Infantry Training School) as well as improvised weapons at Escape and Evasion School.
While stationed in Cuba I was part of the training team that focused on sentry removal training.
And beyond all this...as strong as I was...as tough as I was...I was a small fish...there were many stronger, faster, and tougher within arms reach at any given time.
I found it was the willingness to use the training that made the difference.
Action and reaction in appropriate and measured value.
So without any unnecessary internet feather preening, I think that there are exceptional types everywhere...but in all honesty I doubt too many hang out on internet forums dealing with science fiction dueling with costumes and such.
I am retired, and I do not claim to be elite special forces...my best years of this nature were in the late 1980's and early 1990's.
I do have some special forces/operations training/experience but people need to remember that everyone within the various special forces have people within them that are trained in other career fields...cooks, medics, electronics, admin, supply, etc.. It is a balance of cross training and focus that creates effective special forces...people able to do more with less. I ended up going the support route due my knee, but that is the nature of it...work through 100 applicants to find 10...work through the 10 to find the 1 that meets the basic starting point...take 100 of these types to develop 25 functional special forces types. Desire, talent, potential, etc. is not enough, it all has to come together...avoid injury...get passed the breakdowns...etc.
So the general toughness of mind and body is a common factor within any special forces.
But ALL special forces have specialties and focus of mission, hence the special aspect

You really would not want to meet any of these individuals in the wrong situation...they will rarely be around regular folks...they are not usually hanging out at the Starbucks or comicbook store...they tend to stay on mission track for the entire functional portion of the career path or until they break.
One funny thing that amuses me to no end is how many US Marine Snipers I have met through the years.
Seems that 1:2 former Marines claim to be snipers, until I note that I was in the Marine Corps and attended Battalion level scout sniper training...which is not the full training. And to get to that point I was a three time expert rifle shooter. Again within a service full of great shooters; the US Marine Corps has this down pat, we can all shoot well...some are just better...I was good but by no means was I great.
Great shooters go on to be scout snipers...I trained with various individuals...but in all that time and training, I only met a dozen or so...but afterwards, meeting former and ex Marines (and yes there is a difference) it seems that most were scout snipers.
While training active duty with them I meet a dozen.
While retired I meet hundreds.
About as likely as my light saber being a real light saber and I having jedi powers

*****
Real Combat Training, I have some. Enough to get me through a zombie apocalypse to be sure

Enough to recommend that light saber duels remain friendly

But I also have enough experience and maturity to temper any such training onto a back burner...at least until the zombies start popping up or I meet a Sith...a bad day to be a dark jedi...
