I haven't bought a complete AR in quite some time. I started building my own. In any case, when I build a rifle and am seeking parts, these are some of my considerations.
1. I prefer to go with a milspec barrel. These barrels are finished under the gas block. I don't know that this is important to you, but I'm in south Louisiana and the environment and weather are pretty harsh on steel. I've seen quite a few barrels rust under the gas block because there was no finish there to protect the steel. Milspec barrels are also usually made of a higher grade of steel. Whether the higher grade of steel will be of any benefit to you, I don't know. It depends on how hard you run the rifle.
2. I also like to go with a mil spec buffer tube. I've found them (and this is just personal experience) to be stronger than their commercial spec counter parts. They also usually offer a better fit with aftermarket stocks. The reason that I say that I think they are stronger is because I've replaced a number of commercial spec tubes after the rifle took, what seemed to be a "no big deal" spill. The tubes were tweaked and rendered the rifles inoperable. On one particular rifle, all that happened was the it was knocked off of the shooting bench. The only milspec tube I've had to change was due to the stock whacking a tree while the rifle was strapped to a four wheeler.
3. I like to go with a milspec bolt carrier group, which is going to be the full auto version. They are a bit heavier and help to smooth the operation of the rifle. Some will argue either that staking of the gas key screws is necessary or that it isn't. To be honest, I don't even know if the staking procedure falls within milspec. Still, I prefer to have them properly staked. On the other hand, I've never had one that was properly installed to proper torque specs that came loose, even without staking. Not that I remember, anyway.
4. If I can, I prefer to get a barrel with a pinned gas block. I've had the set screw types work loose on me, especially from those manufacturers that use this type of gas block on barrels that are not dimpled for set screws. The clamp on type gas block are ok. I've never had any problems with them. My current setup has a clamp on installed, but there are still screws that COULD work loose. Whatever gas block you get, just make sure it's steel.
I'm also hearing a whole lot these days about the Smith Sport model. I've shot a few of them and they are nice rifles, for the price. All I want to convey is that first, don't let the fact that their barrels have 5R rifling sway you one way or the other. It's a marketing gimick. I haven't seen anything in use that would lead me to believe that 5R is any better or worse than any other form of rifling as far as accuracy goes.
The second thing I want to mention is just a personal gripe. I'm sure that it was a cost cutting measure, but I can't believe that the trigger guard is integrated into the lower receiver. I don't know what you plan to do with your AR, but I've dinged, dented and bent enough of them to know that I'd rather be able to change a $10 part than have to replace the whole lower receiver.
The barrel is also made of inferior steel. 4140, I believe it is. Still, this may not matter to you and the fact that the barrel isn't chrome lined may lend itself to a bit more accuracy. I just don't know that you'd realize the accuracy benefits, unless you intend to shoot your AR from a bench all of the time.
