I'm basing my opinion completely on my experience with them, not just "well I read...." I'm very biased against them now, after using them. They've caused more problems for me than fixes. Maybe it's the particular system I've had the most experience with (adams arms), maybe not. But some of the issues with it are inherent in the piston AR concept. Carrier tilt, bolt cam pin dragging causing a significant increase in wear in the upper, the piston system affecting the timing on full-auto fire causing it to cycle too fast and click on an empty chamber, the bolt carrier being too large in the rear (to accomodate for carrier tilt) to properly fit and cycle in some buffer tubes, systems being problematic on short barrels, only working with 2 rail systems, and bushings/sleeves coming loose in the upper receiver causing cycling to stop, are all things I've run into with piston systems. And noticeably stiffer recoil. What are you basing your opinions on?
And adding more places on the rifle that need cleaning, making it more time consuming for me. But I've read online that they're easier to clean. :rolleyes:

