Better in some ways, worse in others:
Works with standard magazine.
Works with standard bolt.
Ammo will cost less.
Less muzzle blast.
Theoretically better at short range from short barrels but 6.8 is better at long range from long barrels.
6.8 will have many more loads for some time but we will make the few loads for the 300 AAC BLACKOUT that really matter for most uses.