Well, I am gonna sit the fence on this one since I happen to like and own both the M1A, Garand, several mini's and several Ar's as well as many of the other military type warhorses. I like a good firearm regardless of the make or type. I love the feel of the mini, garand, m1a, and ak's wood feel, however I like the lightweightness of the newer ar platforms. All are great firearms, and have their weak points as well. I look at them all as a piece of history with its own unique story to tell. I will admit the Ar isn't for everyone, or the Ak or many other past military style firearms. I guess to each his own but I can't help but think of the many points various posters have had on here and my thoughts.
The Ar and simplicity..
In my opinion the Ar is more a simple rifle than most including the M1A, and garand. My reason for this is how many nongunsmith people can dissassemble a garand or m1a trigger tweak it and gain perfection without issue, now think about the Ar, two pins swap it out and your done. How bout swapping calibers? I feel the Ar is more Do it yourself capable than some others on the market. That appeals to many now days including me. That however doesn't take away from the fact the M14, garand and mini aren't great firearms.
The vietnam era ar and its problems from my point of view..
I didn't tote an m16 in vietnam so i don't detract from the brave men and women that did including my family. I have a deep respect for soldiers and them doing there job so the rest of us can be free. If I was in combat I would want the best there is
period no matter the make or type. I feel every new product has its share of problems, but if you have researched history alot of the M16's problem was that it was fielded and told to the troops that it never needed to be cleaned. Any gun has to be cleaned to insure desired operation, except maybe the Ak

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Another point to consider is the type of powder used in the original was ball, which if your an ar shooter or reloader you know that ball is dirty compared to the stick powder the M16 was designed to use. From history we can thank Robert Mcnamara for his cost saving idea of switching to ball powder to save money, and the army for not telling the troops of the maintenance the rifle needed. Thats why later (PM) preventive maintenance magazine was fielded to the troops in that conflict, and some issues were resolved. remember the military still uses the same basic designed rifle since 1963 I believe it entered service, correct me if I am wrong.
For example look at the Garand, its original design had a gas trap instead of its later setup, it changed because the first design didn't work so well. Or you could think of the much debated issue of the enbloc magazine "ping" upon ejection. Its still a great firearm anyhow. Just ask the germans that faced it in WWII.
I also think about a story I read about the israeli soldiers armed with the FAL. They hated the weight of the weapon and complained often. That all changed when the soldier used it in combat and his enemies met the business end.
Ok as far as simplicity compare it to the first time you guys field stripped a ruger mark series pistol. In my opinion the Ar isn't any where near that complicated. But the Mark pistols are great never the less. And after a few field strips its easy....some what!
In the topic of accuracy the Ar is in my testing as accurate as the bolt guns I own. I have shot a penny at 100 yards with my 308 ar scoped with a 4x12x50. You cannot see a penny at that distance with my scope, I have done the same with a model 70 winchester in 7mm magnum same scope setup. In addition I have shot equally tight groups under 1 moa with the garand, m1a and mini at the same distance. So I know they are all more accurate than they are given credit for and alot of people are capable of.
I guess I look at firearms and the people that own them and I can compare it to shoes. We all wear shoes, many different types from boots to sandals, to sneakers( just ask my ole lady). We buy what we buy because they are comfortable to us and appeal to our tastes and task we plan to accomplish with them. Same as with firearms to gun owners. We shoot or own the rifles we do because they appeal to us. That doesn't mean one is better than the other just that it fits our personal tastes. Same as one poster put the difference between chevy, ford, and dodge owners, and harley guys and honda guys. We buy what we like and thats part of what makes america great. I hope it stays that way.
So is the Ar a great gun, yes for some no for others. How about the mini, same answer. Also add the m14, garand, ak, model 70, the 1894 lever and other firearm masterpieces. So as long as there is an option to choose what we want the debate over these guns will be around, probably after we all turn into dust.
So I will get off the Soap Box now..