Finished up my ARX-100 review... Here are my thoughts:
Sustains:
-100% reliable to date
-Accuracy is just fine on mine (I know some folks have had different experiences)
-CHF CL barrel
-Extremely ambi-friendly
-Stock seems pretty solid
-MP barrel, bolt, bolt carrier
-Easy maintenance (once you do it once or twice)
-Comes with BUIS
-Leightweight
Improves:
-Not all AR mags work (most do however)
-Rail/Sight height is higher than ARs so some optics will give a chin vs. cheek weld
-Rail space is limited vs. other carbines
Here's the full review with the gun in action: