This is the best red dot sight I have ever used. It is really rugged (like the ACOG it piggyback's on), and is bright in all lighting conditions. It does not strobe (like Burris Fastfire) or get really hard to see in the dark like the tritium RMR. The only functional downside is that there is no off switch or cover for it, but the battery does last 4 years. If you can afford the high price and want a small red dot with the same durability as an ACOG go with this sight. The 8 MOA RMR works great on top of a magnified ACOG. And the 4 MOA would probably work better for more precise shots if it was the only sight on your gun or for a pistol.
Pros: Bright in all lighting conditions, does not strobe, rugged
Cons: expensive, no protective cover, no off switch
This review was written in the old system and had content requirements that are different than reviews written today.