I think some of us are falling into the trap of using too broad an argument here.
I can see merit with both sides on the experience value debate because both are true in different situations.
I think the key determining factor in whether 'combat experience' is of much worth is to assess the risk factor.
The biggest difference between dynamic opfor training and real combat is how being in mortal danger affects people. That cannot be simulated without unacceptably high accident and casualty rates, and thus is, in my view, what really sets combat apart from the most demanding training realistically feasible.
Now, applying that 'rule' to the Air Force, navy tank corps and air defence units, we can see that real combat experience against the likes of Iraq, and especially Afghanistan and ISIS is of very limited value, if not being worse than actual training.
Firstly, those opponents have no assets capable of threatening coalition aircraft or warships other than maybe suicide attacks against planes at airports or ships at port.
Sure, pilots and crews of active combat missions get to do a lot of things they would not get to do as regularly in training, but realistically speaking, what does dropping the hundredth PGM teach you that you would not have already learnt in training and during the first 10 or 20 launches?
It is no accident that USN carrier pilots have to undergo long intensive training periods after they rotate home to catch up on all the regular training that they missed out on while on CAS duty or dull bombing runs.
Its a similar story with the navy, and many other services.
However, the army, marines and especially special forces are fighting a hopelessly outmatched foe, it is true, but in their arena, the scales are not quite tipped so much that the enemy has not effective way of even attempting to strike back.
The large coalition casualty lists can attest to that.
Special forces especially often deploy in small units far from friendly support. If they are rumbled, there is a good chance they would get overrun before they could be extracted or reinforced, as has actually happened more than once.
It is still not the same as fighting a near-peer foe with well trained troops and modern equipment, but it is still the kind of experience that no training program could possible match without the aforementioned high casualty rates, which would be totally unacceptable for peacetime training.
In a way, the old Chinese Chu parable reinforces the advantages this sort of dangerous, but not too much so, combat experience. As the Chu found to their cost, you don't want to fight too many hard own fights, because even if you win, you loose a lot of men and materials.
Its no good putting your troops into too testing a crucible of war if that causes too many of them to perish with all their hard won experience and knowledge.
The closer the enemy is in capability to yourself, the greater the risk in engaging them in combat. The more risks you take, the higher the overall odds you'll end up dead. Its simply logic and statistics.
In a fight against a near-peer, especially a long one, the contrasting strategies and outcomes of the IJN and USN carrier pilot cardres are good illustrative examples.
At the outset of war, the Japanese pilots were as good, if not better trained than their American counterparts were.
The big difference was that the Americans regularly rotated their best pilots out of front line combat to serve as instructors back home, whereas the Japanese kept their best pilots at the front.
As the war progressed, statistics started to bite, and the best Japanese pilots died off at a much faster rate than their American counterparts. As the Japanese started to run out of good pilots, they pulled instructors out of flight school and sent them to the front lines as well, and they were eventually killed off as well.
At the other end, as America rotated back more and more experience pilots back home to train their greenhorns, the quality of graduate pilots improved as well.
I think that is a more modern version of the Chu parable, and serves as a reminder that there is a limit beyond which too much combat against too skilled and capable a foe is actually detrimental to the overall combat effectiveness of your forces.
However, with regards to Special Forces in particular, I think the current lo wish intensity conflicts the US and coalition partners are engaged in are almost the perfectly balanced sort of war to give their special forces the most experience for the least risk and loss.
One can debate just how transferable all that experience is when it comes to fighting an enemy with modern gear, decent training and the full support of a modern military industrial complex, but I think there can be no denying that western special forces will have that little extra compared to those who have not fought in real combat before.
I think the biggest question marks over the effectiveness of western special forces against modern near-peer enemies would be how well they can operate without the total battlefield dominance and full spectrum support they have become accustomed to.
In addition, one has to also ask the question of just how well they have retained all of their skills, specifically the skills that they would have no cause of employ against the mind of foes they have been facing.
I think all of us how have been in work for a while would have looked back in a mixture of regret at all the quick maths or famous quotes we used to be able to do in our heads with no problems or recite line and verse, but which we cannot do anymore without the aid of a calculator or smartphone internet search.
With the best will in the world, the same would happened to special forces operators who have been out in the field for years. Especially since western special forces tend to granted special privileges and dispensations denied regular line troops. Which may exacerbate the situation.
Obviously no good operator would like essential skills they will need out in the field atrophy, but what about the skills that are of no use fighting the Taliban, but which are of critical important against an enemy with modern top of the line equipment?
I doubt your average western SpecOps operators spend much time practicing never mind employing camouflage against enemy air power out in Afghanistan or Iraq. And I doubt they spend much time devising ways around high tech motion sensors, or how best to counter enemy thermal imaging gear like PLA special forces spend a lot of time doing.
So in conclusion, I think in the kind of skills they would be needed to employ regularly out in the field, western special forces would have the upper hand against their PLA counterparts or any other operators who have not seen actual combat.
However, I would not be surprised if the PLA guys turn out to be better practiced at the niche skills and disciplines most suited to fighting a high tech opponent.
