Except for the first one I looked at, which had a noisy magazine, I kind of like them. The last couple I've seen were pretty impressive. Basically, you get a whole new gun to play with for the price of a barrel ( not installed! ) for another rifle. Hard to argue with the math.
I may get a .223 after the current crop of new arrivals is settled in, although the AR 556 is also a great deal and I've yet to play the Black Rifle game.
