I received my new "Enhanced Chamber Lock/Adapter". All I can say is, its certainly a very well thought out and machined part. Just looking at one can tell that it will perform much better than the older style kits. In all the past designs there was a chamber adapter that sort of fit in where a standard 5.56 round would go. Due to the slip in nature there was the possibility for that adapter to move about as the rifle was fired and the bolt cyclled. This subject has been well discussed before. With the lock on the new adapter this variation has been eliminated. The adapter is now firmly locked into the chamber area and will be consistent round after round.
We are still using a slightly undersized bullet with the .22 LR round. That variation will always be there. But, the variation in the placement of the chamber adapter and how it fits up against the internals of the barrel has now been eliminated. This alone will make the accuracy of the rifle improve and be more consistent. Every variable that can be reduced or eliminated will improve the operation and accuracy of any firearm. Ammunition is important too as has been pointed out. With this upgraded adapter and decent ammo like CCI you can be pretty confident that your rifle is going to shoot far more consistently. While no one should expect target rife performance I think most will find that this combination will perform quite well for plinking and practice at the range. I find it is more accurate than the AK rifles I use to shoot. Those things were like shotguns! Also, I find that it will shoot as accurately as many of the so-called "Tactical .22's" that are on the market.
So, one can just decide what fits their needs. Since I have several 5.56mm AR rifles I find that a good conversion kit is a nice accessory to have. It saves me a lot of money, its easy to shoot, and it is plenty accurate enough for much of the shooting we do. I shoot a lot and I appreciate good equipment. Yes, its a couple of bucks more for the "Enhanced Chamber Lock/Adapter" but for me, and many others, its well worth it. The price difference is not that much and what you get is simply "the best" that is available. Besides that, it looks so cool compared to the older designs.