I actually consider the Armalite AR rifles to be overlooked. The new ones have excellent fit/finish on them (I seem to recall that the Aero forgings are the same). Compared to my LMT and Stag the Armalite fit/finish is right in there. The Armalite also has the dry lube finish in the upper like my LMT. The staking on mine looks to be right and is the same as my LMT and Stag. Pretty good rifle. On a side note my Armalite DND AR10 is on my never sell list.
As for the twist rate. I see a lot of people going for the 1:7 twist. There's nothing wrong with that, but as I recall the reason for going to this twist rate was to stabilize the 62 grain ammo in extreme cold, not to shoot heavier ammo which out of short barrels loses a lot of steam anyways. Having done some shooting in -30 and refused to leave the house when it was much colder, I can tell you that for my personal use I don't enjoy shooting in that temperature. As for police use which like the military could very well be in extreme cold. I've had to work in sub -50 temperatures so it's definitely a reality.
Given the choice I'd go with 1:7 but it does generally mean more expensive and harder to get ammo if you want the most accuracy. Unless of course you get lucky. Which could happen.
Absolutely.
The lowers on these like the LMT are 5.56mm marked. If the barrel is also nato marked in 14.5" then it is worth a premium. The Armalite does have some military/police sales. The AR10 was used by Canadian spotters in Afghanistan, the AR15 is in use with the Illinois State police. But yes it doesn't have the same sort of "reputation" as the LMT and others. Personally while I really like mine, it is my lower level most basic AR15 in my safe. I bought mine as a police carbine and wanted to keep it simple. For that very reason I actually prefer the 1:9 twist. I plan on shooting 55 grain ammo out of it and keep it cheap.
X2, especially in the current market. I would also hold onto it and not sell at this time. Plus I happen to like Armalite

and I consider these rifles as better than their internet street cred would leave you to believe.