Just like software, don't buy version one of anything...
Also, there are many products out there that are suitable for competition, but simply are not appropriate for a good tactical rifle.
If you want a pneumatic buffer, then an adjustable gas system would be appropriate for tuning. An o-ring sealed pneumatic tube is simply not as soldier proof as a spring and a piston.
Stick to pure breds. A tactical rifle is built tough while sacrificing delicate refinement, but it won't win any benchrest competitions. A race gun is built very accurate but wouldn't survive a day in the bush unless kept in a Pelican type hard case and then handled gently.
So, if you want to shoot SAAMI spec ammo at paper targets while minimizing recoil to get overlapping holes in your shot group, a pneumatic buffer and adjustable gas system would be helpful.
Likewise, if you are bump firing beta-mags full of milsurp ammo at old Maytags and Toyotas, the "sproing" is the least of your worries.