[leonz66]

Hi, Folks.
I have to mention, that I'm not engaged by either manufacturer to promote the stuff. It's my own test, nothing more.
Here're some more notes if you're interested. Many people, including very senior shooters believe in Glock Perfection and 200.000k rounds lifetime.
Without arguing, I'd say the following:
Based on my tests, stock spring does not create much impact on a frame with 115gr. ammo. For a while you don't shot heavy loads and your spring has no degradation, you can be safe without the buffer.
However, springs tend to weaken. Based on some measurements, stock 17lbs spring can became 14lbs after about 3000-5000 rounds (saying can, not obviously will). The spring also weakens just with the time, in a year-two it can get to 14lbs. I'd made a trial to figure out how people can recognize their springs went bad. I've made a dozen of single-use buffers of the same shape, cut by knife from the simple thin vinyl. Then, I've asked people in our shooting club to place this piece on their glocks and shot some 50-100 rounds.
As you may guess, about 70-80% of them revealed deep signs/cuts on these gaskets. Thus, I knew that slide hits the frame pretty frequently and people are ignorant about it. We mostly do not feel how it weakened, the gun still shots well and we start to absorb the extra energy in our hand/elbow joints.
I'd say, our joint tissues are not better than specially designed shock absorption polymer. Of course, the frame and slide are also suffering, but these are easy to replace, unlike our joints.
Next, please consider people often use reduced springs to achieve quick follow-up shots. And 11-12lbs is the common way to go. Certainly, the impact is much higher.
And the last. Blazer is one of the softest recoil ammos. I can definitely tell you that Winch. 115gr. hits significantly stronger and with the same setting the buffer won't survive even 1000 rounds.
Certainly, with the .40 the game becomes much more tough and the buffer can help to save your elbows.
There's no recipe. It's just FYI.

As about the felt recoil. I was honest with my test but this means I only wrote what I was certain with. I generally don't care much on recoil, not with 9mm. I can't even say whether I feel any difference between buffer installed and removed. I really don't care on it and only interested in how quick I can get muzzle on a target back. I tend to say that with the buffer I can place a follow-up better. But it could be a purely "placebo" effect. I can't prove it and hence, do not mention in the test.
But again, I believe my elbow (pretty damaged by tennis and age) dislikes the buffer-less Glock with reduced recoil spring. Even I never lock my elbows, I feel that after some 300 rounds.

Thanks for discussing and sorry if I'm saying something you don't agree with.