Which Upper? Actually Gas Piston v. DI

[Bart Solo]

I have been looking at light weight uppers.  I can acquire an Adams Arms gas piston carbine length upper for about the same cost as a carbine length BCM upper.  BCM has a great reputation and I can be sure the parts are completely Mil-Spec including a chrome lined bore.  Adams Arms has a well regarded gas piston, but I am not sure the Adams barrel is as good as the BCM barrel.  All sorts of people say gas piston technology is the future of the AR platform.  Gas impingement technology is 50 + years old and is well proven.  There are fewer moving parts so less to break. On the other hand heat and crud are the enemy of any piece of equipment I have ever owned.  I know I can find gas impingement uppers for less from a variety of sources, but I am looking at a price point of $600-$650.   The price point Adams Arms and BCM are also looking at. 
 
In making my decision I am thinking about reliability and accuracy.  Which would you choose? 
 
By the way, BCM doesn't sell complete uppers.   They sell upper assemblies (barrels, gas systems and upper receivers).  They sell bcgs, charging handles and furniture seperately, which makes sense considering how modular ARs really are. My price point includes a bcg, charging handle and handguard.   

[cjclemens]

I think gas piston is definitely the future of the AR platform, particularly when talking specifically about military applications.  That certainly doesn't mean there's no merit to the original direct impingement system, either.  I think this choice should boil down to your personal preference and shooting style.  If you intend to do a lot of high volume shooting, you might benefit from the gas piston system.  Any more, I rarely shoot more than 1k rounds through my target/coyote hunting AR and it doesn't get too dirty - even though it usually only gets cleaned 2 or 3 times a year.

I cant imagine accuracy being a big issue either, unless the weight of moving parts in the gas piston system has an effect.  Even if it does, it should be negligible.  Personally, if I was building a new AR, I'd probably go with a gas piston system just to try something new - especially if I was building a tactical/personal defense rifle.

[demented]

 I'm no expert but have been shooting AR-15's since 1974.  Own or have owned at least two dozen, shot literally thousands of rounds through them.  I have yet to see the first malfunction that was caused by direct impingement.  Malfunctions are usually bad magazines, bad ammo, crud getting between the bolt carrier and upper receiver, this clogging things up.  None of these problems would be any better using a gas piston type upper.