I have two RRA AR’s, a predator pursuit and an M4 type. Both are very well built and smooth operating. The predator rifle met their accuracy guarantee with 55,68, and 69gr bullets. Two were my hand loads and the 68 was a remanufactured ammo I found a good price on. I lucked into both of them and have no regrets at all. I have no experience with the other brands mentioned. Compared to the Windham and DPMS guns I have, RRA is head and shoulders above them.