I don't have any experience with LWRC but can tell you that the piston systems is nothing more than a way to sell more expensive rifles.

The theoretical benefit to a piston system is that it supposedly is a cleaner gas system than direct gas impingement and therefore more reliable because it keeps carbon out of the receiver and bolt body. Extensive testing shows otherwise.


I suggest that you take the advice from this thread over at the firing line. Especially WJKULECK. He lays it out far better than I would be able to.

http://thefiringline.com/forums/showthread.php?t=291416