The Atlantic magazine recenly published an article that is drawing criticisms from more knowledgable people. In the article Robert Scales questions why the military is not fielding better weapon than the current M4.
The Atlantic article: http://www.theatlantic.com/magazine/archive/2015/01/gun-trouble/383508/
Nathaniel F from The Firearm Blog wrote a piece pointing out some problems with The Atlantic's article
and so did Ranger Up.
It seems like debate of which gun to use never has a time off.
From: The Atlantic, The Firearm Blog, Ranger Up