I'm about to pull the trigger on my first owned ACOG. It will be put on a .308 AR-10 for 300-400 yards shooting. I noticed that the reticle is amber not the usual red or green. Is there any advantage/disadvantage to the amber over the other colors? Is there any other robust optic out there that is comparable to this ACOG? As you can guess, price isn't too much of an issue; just looking the best bang for the buck.