dBent, as you've seen, opinions on ARs vary widely. As I stated before, I consider the likes of Colt, BCM, Daniel Defense and other of that class to be a step above the likes of Rock River, Stag, DPMS, etc.
I have more experience with ARs than most and not as much as some. Of the dozen or so ARs that I've had, I only bought one complete rifle. I built all of the others for varying purposes from M4ish builds to precision rifles. I've also built rifles for friends. I've used parts from varying manufacturers. I've also become somewhat of the AR expert among the people that I know and shoot with and have fixed many more rifles than I've built.
What I've found is that there are a lot of good manufacturers out there that build rifles that will get the job done. I expressed the opinion that I did based on one simple thing. That is the likelihood of having problems with any particular brand and I ranked those that I felt were a rung above the others based on the fact that I've seen fewer problems with them.
If you are experienced with ARs, know how they operate and know what each part does, then you can likely buy some third rate rifle at a bargain and likely keep it shooting the way it's supposed to. On the other hand, if you don't have a lot of experience with ARs, then a very minor problem can have you tearing your hair out and having to ship a brand new rifle back and forth trying to work out a problem.
I've seen DPMS rifles with pre-mature ring failure. Extractor/spring failure. Barrels torqued so tightly that the POI did weird things when the rifle heated up. Barrels that were so loose that the handguards shimmied back and forth.
On Rock Rivers, I've seen pre-mature trigger failure on the two stages. Canted front sights. Misaligned gas blocks. Extractor failures, etc. The same with Stags.
I won't say that I've never had to fix a Colt, BCM or Daniel Defense, but those that did need fixing were due to have some parts replaced due to use.
My point is that for a first time AR owner, you will have a better chance of not running into problems by going with an upper tier manufacturer.
I will say, however, that the guys that I know that got into Delton rigs seem to like them and I haven't seen any of them tearing their hair out. I'll also say that Smith and Wesson has made it to the list of OK'd makes for some LEO departments where I am and those guys aren't having any problems with those either.
A popular rig, just based on what they tell me when I see them in court and around is some flavor of Smith with an Aimpoint Pro package. The guys that are getting them have to buy their own rifle and this combo has been a good bang for the buck for these guys.
Now, I don't want to open a can of worms with this and this is just what I've seen; but the "better" makes seem to have fewer problems running steel cased ammo, if that matter to you.
On a last note, whatever you get, I'd recommend some flavor of 16" with a midlength gas system. You'll be less likely to suffer some of the common problems associated with the carbine length gas system.
