I hope to have my first carbine length gas system rifle up and running by the end of the week. I was thinking of using a PSA H2 or H3 buffer in it but then I saw this video.

Mentioned therin is a new buffer made by American defense. Its recoil dampening properties seem impressive but it costs twice as much as a regular buffer and it looks like it is so new on the market that AD is the only outfit selling them at the moment.

I know that AD makes good stuff but does anyone here think it would be worth it to be an early adopter of this part? Or should I just go with the PSA buffer? Or perhaps something else entirely?

Give it a try. ADM's website says it weighs as much as a rifle buffer, so that makes it 5.2 oz.

Spike's H2 ftw

Spike's is labeled as T2, not H2.

H Buffer: 3.8 oz
H2 Buffer: 4.6 oz
H3 Buffer 5.4 oz

Spike's Tactical T2 - 4.05 oz

I would go ahead and start of with a standard carbine buffer. How would you know you need something heavier if it hasn't been shot yet? If you start off with a buffer that is too heavy for the rifle it will likely short stroke and malfunction.

Oh, I have plenty of normal carbine buffers lying around. I will definetely do a function test with one of those first.

I use RRA 9MM buffers in all my Carbine lowers no matter what upper is on top.
Runs fine.  I think they're 5.3 ounces? or so.

95% of what you see about buffers is snake oil, misinformation, and bullhockey.

The most significant factor in felt recoil in the AR platform is how overgassed it is (or isn't). Much of the impact you feel on your shoulder isn't actually recoil from the bullet being pushed out of the barrel, it's the impact of the bolt carrier slamming into the back of the buffer tube. If the gun is overgassed, adding a heavy buffer can absorb some of the gas impulse energy and keep the bolt carrier from slamming into the back of the buffer tube as violently, which will reduce perceived recoil.

But if you put an adjustable gas block on the gun and turn the gas down, you can run a standard or even lighter-than-standard buffer, and cycle reliably with less felt recoil than you'd get with a heavy buffer.

There is a tradeoff between felt recoil and reliability. If you turn the gas down to the point where cycling energy is only 1% more than the minimum needed to cycle the action, felt recoil will be minimum. But a mimimally undercharged round or any amount of fouling is going to cause short-cycling failure. If you turn the gas up so the action is cycling with 25% more than the minimum energy needed to cycle the action, you'll have excellent reliability, but increased felt recoil. You'll need to do your own testing to determine where your rifle's sweet spot (low felt recoil and reliable cycling even when fouled) is found.

3-gun match guns commonly employ lightened buffers and bolt carriers and adjustable gas blocks. Competitors commonly fire hundreds or thousands of rounds during matches and cycling failures are not acceptable. Recoil needs to be minimal to minimize split times between shots.

I wouldn't go so far as to say that a lightened buffer and bolt carrier is ideal for a HD gun, but the notion that something heavier (and much more expensive) than a standard carbine buffer is needed for reliability and low felt recoil is a myth.

The only time a heavy buffer is really needed is with 5.56 guns with pistol-length gas. The heavy buffer slows the bolt and carrier a bit so there is less chamber pressure when the bolt unlocks. If you reload, that means you have less resizing to do, and a case separation is less likely.

From:  MidwayUSA web site and Spike’s website.

DMPS Carbine = 2.9 oz.    
         ST-T1   = 3.00 oz. Actual weight can vary between 2.9 oz and 3.1 oz.
    H Buffer   = 3.8 oz
    ST-T2   = 4.05 oz. Actual weight can vary between 4.0 oz and 4.2 oz.
  H2 Buffer = 4.6 oz
   H3 Buffer = 5.4 oz
     ST-T3  = 5.40 oz.  Actual weight…..not specified on website