I put the apex fss in mine and I love it. My friend kept his stock and just polished a few areas and he loves his. He has more rounds through his than I do. His has a long smooth consistent pull where mine has a very short light break. His is used as a nightstand home defense and mine is...
I'd take my RRA AR-15 with my cmmg .22 conversion and my AAC aviator. I could switch from 5.56 to some very quiet .22. Rounds would be light and both are adequate for hunting and neutralizing a threat.
I have a core and hated the trigger. Swapped it out for the apex fss aluminum kit. That made a world of difference. I'm still adjusting to the high iron sights while I save up for a red dot. The gun is very accurate.