Both calibers are in different areas of use. One intended for suppressed use in a AR platform most likely along the terms of self defense. The other is an all around great round that can be used from varminting to killing decent size game. Out of those two choices, unless you have a thing for the blackout and have an application for it the .308 will suit you better in every department. That includes, price, long range shooting, game, and more than likely accuracy. The .308 has been around for quite some time now, and there is so much data on it. It's just one of the easiest rounds to load for or find ammo for. I vote .308 between those two.