Marketing plays a big role it "which AR is the best". A lot of people comment and share their opinions based on marketing or anecdotal experience.
I would bet most people haven't had first hand experience with the "top tier brands".
KAC, LMT are considered by many to be the "best"
LaRue, Wilson Combat, Daniel Defense and BCM are considered by many to be " 2nd tier".
Others consider Rock River, Spikes and JP, Aero as "2nd or 3rd tier"
Many of these manufacturers have a 1 moa guarantee.
Some are built better than others and some use components I prefer like the JP silent spring.
I have or have had one of every rifle on this list and I can tell you a Rock River Coyote Carbine will shoot and function as good as any on the list. I use BCM home defense, Larue for target Andy Rock River for hunting because each is different.
My 2 cents, is to lay hands on as many as you can and determine the purpose of the rifle because it makes a different before making the purchase