"I just ordered a Del-Ton rifle kit. I did not need a whole kit but it was on sale so it was only $15 dollars more than a complete upper only. I have not seen Del-Ton mentioned so it must be in the middle somewhere. kwg"
I tend to avoid these topics becuase it too quickly turn into a "if you spent less than 2k for you Ar you bought junk" or if it isn't compared to the now-outdated "list".
Anyway, my wife and run Del-Ton. Mine is a complete M4 from them, hers is a light-weight carbine on a new "2013" Olympic lower.
We most shoot recreationally, I do more hunting and longer range work than she does. We both just got done with a CQB course and they both ran wonderfully. zero stoppages that were the rifle. Some ammo issues, but that is off topic here.
Anyway, it comes down to how well a rifle is built. There are only so many companies making receivers and parts. Mostly it is crap shoot. I have seen $500 AR's run all day, I have seen $2000 AR's that wouldn't run at all. I just watched a friend fight his Sig AR at the range the other day. All you heard were cuss words when the rest of us were banging away on steel plates. I know Sig makes top-rated firearms, but his has issues.
Anyway, as for who to avoid, I can't say there is one to avoid all together, but with the deals in AR market right now with all the over stocks, it is easy to find a nicely built one from a good solid company.