I have an AR15A2 I built decades ago, that I used for plinking, Target Shooting, and DCM/CMP Matches. With the few modifications I've made to it, it's no longer CMP legal for Matches.
As the Rifle Range I used to shoot at closed down, I've not shot it much lately, but it's still a very good Rifle, accurate and reliable. I do like the idea of having a 20 inch barrel to wring out as much energy as is possible with the 5.56/.223 Caliber.
I have had the itch to build a flat topped 16 inch free float barreled AR Carbine, but with no access to a Rifle Range, it's not been a priority. Currently, my Ruger Mini-14 Scout, Egyptian Maadi AKM, and my much fussed over Century Vz2008/Vz58 serve as my go to Tactical Carbines.

AR15A2

Ruger Mini-14 Scout

CAI Vz2008/Vz58