I've never heard the military complain about Trijicon ACOGs. That's because they just work...year after year, war after war, decade after decade. Few optics have amassed their amazing war record. ACOGs are built like tanks with heavy duty forged aluminum housings designed to be totally waterproof and shock proof. Imagery is bright and clear and the glass and coatings are the best available. Many different ballistic reticles are offered and most models will give both fiber optic and tritium illumination. Some models [see below] will come with piggyback mini red dot sights or top mounted BUIS.
You will have to decide on your magnification choice: these are not variable power optics as Trijicon eliminated that complexity and point of failure. Reticle considerations are discussed in the video review with Mrs Nutnfancy helping out on the AR-15. Also be ready for the substantial cost and 15 oz carry weight. The review will show perhaps a better civilian option that is versatile and competition proven. Nevertheless you can't go wrong with an ACOG and it will outlast YOU. The one we bought for this review is heavily used and it keeps on truckin'!
Vortex Strike Eagle RifleScope (1-8x24) Xlnt $488, rec'd for most users over ACOG and you'll save $600!: https://amzn.to/2Izilio
Trijicon ACOG all models recommended: https://amzn.to/2IBCvIz https://amzn.to/2Gxkeu8
Trijicon ACOG 4x32 BAC Dual Lume: https://amzn.to/2kdtniJ
Trijicon 4x32mm ACOG Crosshair Reticle with 3.25 MOA RMR Sight [freaking awesome optic]: https://amzn.to/2KztcJK https://amzn.to/2rXLOf3
ACOG Accessories: https://amzn.to/2IADYPz
Leupold VX-6 HD CMR2 Reticle, Illum [xlnt scope]: https://amzn.to/2LePpye
Weaver 849780 Optics Kaspa Tactical Scope, 1.5-6 x 32mm, Dark Earth : https://amzn.to/2IuIVxj
(review coming up)