Another vote for the SR-15E3
From what little I have read the E3 bolt design is apparently superior in strength and longevity to Milspec. I wonder if controversy about the design will be occurring in a few years since all manufacturers may be using it or a variation. I also voted with my wallet last August when I bought an SR-15 from Scottsdale Gun Club. Before making my purchase I had the opportunity to handle in an afternoon one or more examples of product from just about every AR-15 manufacturer. Living in Scottsdale makes this very easy to do because across a sidewalk from SGC is US Autoweapons and three miles away is Bear Arms. These three dealers always have a large and diverse selection. Of all the AR-15 variants available, nothing equaled the handling and features of the SR-15. I have shot a few rounds through other peoples various ARs both DI and Piston over the years and many thousands of rounds through my own previously owned Colt AR-15A1/A2s and U.S. Army M16A1/A2s. The last three months of shooting confirmed in my mind that nothing feels as good shooting as the SR-15. Today or tomorrow I will test out my new Surefire Mini suppressor with the hope that reliability will not degrade. By the way, going the Trust route seems to be the quickest way to get the stamp as I received mine two months to the day of application.