Re: ELCAN OS4 or DR 1-4
In my opinion the OS4 gives up the greatest asset of the DR, the ridiculously fast 1/4 power switch. I see little use for fixed 4x scopes when 1-4x designs are used on 1x the vast majority of the time. As for the ACOG, it is light, rugged, and has always on illumination. These are in its favor. In summary, the DR gives you more but has more weight, the Acog is lighter and simpler.
What do I think? I recently replaced an Acog with a Specter DR, that is what I think.