Lone Gunman, that was my point. If you asked which is the better rifle, the Colt is clearly the better rifle. If the next question was - is it that much better that you'd likely notice, I'd probably say no to that. We agree on that.
The QC Colt does, the staking of the carrier key and the castle nut, and other things most likely won't come into play. That's your point. Some things, like F height front sights sometimes do for some people.
Some people like to know the difference, and want the rifle that is better, no matter what its better for, regardless if it will actually play a role. Some people feel the extras Colt offers are well worth the price difference. Many Colt bashers exaggerate the price difference between a Bushmaster and a Colt. I personally believe that the Bushmaster is overpriced considering what it has less than a Colt.
I think the Bushmaster is a nice rifle. I'd take one over a RRA anyday due to a chrome lined chamber and bore with 4150 steel and true 5.56 chamber (although the Wylde is a good chamber too). A chrome lined chamber and bore outweigh ANYthing RRA has to offer in my opinion. I been thinking of building a superlight using a Bushmaster barrel. I'd also use the Bushmaster LPK as I feel it is the best (after Colt's LPK which costs 2x as much, but is the best, and you can see and feel the difference).
Colt is better in all other areas. I can't find a single area where the Colt has a weakness and Bushmaster is better. Most of the anti-Colt stuff is politically oriented, and often based in unsupported rumors.
The thread's author isn't comparing apples to apples. The Colt is a neutered gun, the Bushmaster is a no-ban. If you go Colt, the choice is either a 6920 or a 6520. The first being the closest thing to a real M4, and the 2nd being a pencil barrled A2 carbine.