Colt makes a great rifle. They have a reputation for making very reliable rifles. They take some extra steps when testing and assembling components. HPT, MPI, carrier key and castle nut staking, etc. These are extras that are optional on a predator rifle. These differences will likely never be noticed by the average predator hunter who shoots a few rounds at critters and does a little target shooting. Where the difference shows is when the rifle is ran hard like in a weekend carbine course or in depth LE training where 1-2 thousand rounds might be fired over the duration. Many of the budget ARs are going to suffer from failures and not make it through the course.
For a long time Colt screwed themselves by using some less than desirable manufacturing techniques such as oversized trigger pins, receiver blocks, nut and bolt in place of a front receiver push pin. Their rep suffered big time for this. Recently they have corrected this at least on their LE models. ( Not sure on the others)
Used to be there was no reason to consider a Colt for a predator rifle at the high prices being asked. Prices have dropped considerably for some models though and are quite competitive with the budget guns now. The same accuracy enhancing techniques can be done on a 6920 and it would be a fine predator rifle.