If you absolutely want the best, buy a Colt. Only one problem, they are expensive and they are backordered. Colt uses the absolute highest quality materials on all the parts and has the absolute best quality control. You can see the difference everywhere on the rifle. Please ignore the idiotic Colt haters. They know nothing. I speak of rifle quality only. Only problem is, if you can't have flashhiders etc...you will have to settle for their neutered civvie models, which are NOT the same as their LE models which are superior to all other AR's. The civvie ones might not be as good as the LE's but they are most likely still better than everything else out there.
The next up after that is Bushmaster. Bushmaster might not be as techinically good as a Colt, but there's nothing wrong with them and the differences are small. There's no practical disadvantage to owning a Bushy. I highly, highly recommend that you buy the flat top 16" "superlight". 16" is all you need, and that barrel profile is all you need. If you don't want a flattop, it comes in an A2 upper also. Trust me, once you go light, you'll never desire an HBAR ever. There's no purpose for it contrary to what many people will say to justify it. I put Bushmaster above RRA because of the configurations in both pre/post ban availability (which are important for you), as well as one huge feature they all have - chrome lining. That to me is an absolute must. While I own a Colt, I like Bushmaster a lot. Good rifle, good company. They've always been nice to me when I dealt with them.
After that, I'd say RRA. People rave on about these. They're built well, but in my opinion, they aren't that much better than a kit gun. All RRA does is professionally assemble a rifle from the same parts you can buy as a kit or individually and offers you a warranty. I will probably be flamed for saying that as I am stepping on sacred grounds, but it is the truth.
If you are somewhat mechanically skilled and are willing to learn, I'd build an AR from parts. If you buy the right parts, and you assemble correctly, the rifle you'll have will be the equal or better than RRA.
Others are: Armalite (not the orginal Armalite company that first made the AR), people regard them as high quality. Olympic- about middle of the road. DPMS - upper middle of the road. Fulton is a semi-custom. I'd put it in the high quality group, but you can probaby get the same function for less $$$ with other options. Fulton doesn't make any junk, but you pay for that.