People always try to claim a Piston AR is more reliable than a DI, well to be honest its BS, they always claim the AK is sooooo reliable, well it is, but it was designed a piston, but the key reason its so reliable, is it is made with loose tollarances. The bolt carrier does not know if its being hit with a piston, a hammer or a shot of gas. The AR has very tight tollarances, and needs lubed, pure and simple, remember when POF ran their ads about not needing as much? Well they discovered increased wear, on all their surfaces where steel met aluminum (bolt carrier and upper). If you still have any questions on reliabilty or durability, http://www.bravocompanymfg.com/v/vsp...hy14_oct10.pdf
"Filthey 14". All the pistons bring to the AR table, is a gimmick, and a way to sell more AR's in a flooded market.
ETA, break a piston, you will need manufacturer specific parts to get it back up and running.