After playing with two .223 bolt guns and an AR, I really don't think you're going to see that big of difference to be honest in any production gun. However, I do see a difference when attention to headspace was involved. Buy a Mic guage and see how far you are pushing your case shoulder, then the rifle will tell you how to set up. I full size AR cases - always.
I'll take headspace and concentricity as my priorities for production guns.