In my case I have seen the Colt LE 6920 go from $1600, $1500, to $1000 as prices varied over time and political circumstances. My first Colt AR-15 was about $300 quite a few years ago purchased in California. 1975 ballpark. I first qualified with the M-14 in 1972. A few years later it was with the M-16. I would say if you get the LE 6920 you should be well pleased. I can't say anything about other brands now that the AR platform has taken off. I could be right or wrong without knowing either way about how good or bad they may be or not be.
My Colt M-4 style LE 6920 is every bit as reliable, accurate, trustworthy as I could ever epect. Never had any malfunction of any kind. Never had any problems or issues regarding multiple ammo brands, zeroing, POA/POI, or any other. Firing this Colt takes me back to the days when I was a young Marine getting fives and fours and never saw Maggie's drawers.