AR's are different in ways some don't see.
1) They were designed around ammunition that is specifically loaded to provide sufficient gas to operate the action. Military ammo is regulated to do that, civilian ammo is all over the map, because bolt and lever guns can shoot it regardless. Semi auto shotguns have all kinds of ingenious gas valves and regulation to compensate for a bird shot load vs. magnum goose. AR's, no, and it was never intended. Don't get trapped into shooting cheap white box or import ammo and thinking the gun is defective, when it's the ammo.
2) Military Specification and the Technical Data Package: A specific list of requirements is part of the contract to make M16's and M4's, don't think for a minute those demands are state of the art or even current. Military guns are 2 MOA accurate, and shoot a lot more full auto. That means the government requires chromed bores, which are more inaccurate than a precision button rifled barrel, but they do resist erosion and corrosion. Some parts are individually inspected, which commercial makers are loathe to guarantee - it's still a buyer be aware market. And no AR will ever be 100% milspec, because it's not full auto and government accepted. Since 1986, you can't buy one (regardless of the legalities of the decision, which are in serious question.)
3) AR's are usually built to good quality, in that a lot of parts interchange without any handfitting or gunsmithing. If someone can change a water pump on a car, they can build an AR step by step and get a functioning firearm. That's very different from the 1911 craze still going on, parts for them usually require hand fitting, and getting a Government spec 1911 to feed hollow points is a real challenge. AR's aren't nearly so difficult. They do have their distinctive method of operation.
4) You DON'T have to clean an AR to surgical standards, what they need is plenty of oil. That's a big change from the word of mouth practice of most gun owners, who like pretty, clean, and tight fitting guns as an example of what they want you to think about their character. Functioning AR's are more like internal combustion engines - they should rattle, leak oil, get dirty, and only rarely need to be torn down. It's one of those distinct differences gun nerds don't understand, because it's not like their prized manual action. That's because, it's not like their prized manual actions, but the obvious point seems to be beyond them.
Wipe the parts down, keep it oiled, feed it the correct pressure ammo, from a good magazine, it will do it's part. Fail in those requirements, it will turn on you just like daily driver with no oil in the crankcase, a tank full of kerosene, a mouse nest in the ignition, and snakes living under the dashboard. Most actual shooter complaints on forums are owner ignorance or shooter abuse. Just like Jeeps.
