It depends on how you want to use it. I have 2 AR's both Colts one is a 6551 Goverment Model A2 I kept the GI sling on it. I use it for varmint hunting so the rifle usually is carried over my shoulder. I can crawl better in the dirt with this sling and lay the rifle over my arm as I crawl. Keeps the weapon cleaner and out of the mud / dirt better.

My other Colt is a 6920 the front sling attachment is on the LaRue Free Float Forearm. I use it for CQB and is more of a patrol sling so the rifle rests on my chest for quick access and easy transition from rifle to pistol. So it depends on how you are going to use your rifle.

It's more of a personal preference and your intended use. I am about done with my mods / add on's to my Colt 6920. When i'm finished i'll post some pix.