Just the ease of changing the settings and actual marks will take the guess work of settings would be a bonus. Not sure how often the Impact guys are fiddling with the valve adjuster (I doubt every other shot). Stocks can be modified. I don't like the looks of the Impact, I have an M4 it's for use not beauty. The crown reminds me of my Anschutz 1918. Every trigger pull was amazing, the rifle was simplistic beauty.