I have Ar15's and now a Ruger SR556 and Robinson XCR, I notice a vast difference in the action on the piston driven systems. Much smoother, less springy return, I could make up dozens of words to describe the feel of the action, but I wont. Its a better action IMO. I havent fired an ARX, Tavor, Msar, or Scar16, but am seriously considering a Msar and Scar16. I cant get over all the polymer used in these (modern) rifles. I prefer the wood and metal of the AK47 over the plastic and aluminum feel of AR15's. I would like opinions of current or previous owners (Heck, even if you shot a friends) of ARX's, Scar16's , Msar's, Tavor's, any of these comparable to AR15 platform rifles. I have never been a huge fan of AR15's but the improvements to the gas systems have drawn my attention.