I'm not sure I understand the difference between the acog technology and the reflex II technology.

I've personally experienced Reflex reticle washout during range exercises to the point that the dot wasn't visible and the colored lens totally obscured the target, even though we could still see the target with the naked eye. So, I'm considering an eotech. BUT, and acog would be even better if it doesn't have the "washout" issue. ANY HELP?

No it does not however it does have a black out problem.  THis is where you look through the ACOG scope and it its dark and use a flashlight.  The light coming through the scope is brighter than the tritium illumination since the fiber optic tube cant collect enough light to light up the reticle the reticle will appear black just like a standard cross hair in a scope does with no illumination.  If you have a red reticle then you can put on a blue filter on the light and since there is no red to overpower the reticle you will still have a red glowing reticle with the rest of the field of view being lit up blue by the filtered flash light.  If you go search in the flashlight/laser forum NewARguy posted some pics of this a while back.  I have no idea what happens with the amber reticle when a flashlight or filtered flashlight is used though.

Edited to add:

Please use different terminology as the Reflex 2 IS AN ACOG.  Call it full sized ACOG, compact ACOG or just BAC ACOG.

The ACOG doesn't have this problem like the Reflex II for a variety of reasons:

1) No colored lens because it doesn't use a reflective lens to generate the reticle

2) Roof prism generated reticle makes better use of the light

3) ACOG uses standard scope reticle supplimented by tritium and fiber optic lighting so reticle can never completely disappear. Worst case scenario (as noted above) is that the reticle turns black like a normal scope crosshair.

The worst I have been able to do so far is aiming from a totally dark interior room to another interior room that it brightly lit with the door open. There isn't much ambient light for the fiber optic and the tritium is just strong enough to illuminate the reticle faintly. Even in this case, it was usable, just not ideal.