Nice looking rifles gents.

I have a few carbine sized rifles including AR's, AK's and FAL's. My advie on the AR platform would be to keep it simple (resisting hanging too much "tactical" stuff off of it). Start out with iron sites and learn how to use them.

Any top tier manufacturer's 16" A3 rifle should work well for you. A sling, a head up optic (Aimpoint/EOTech), flip up sights and a light are the only additional gadgets on my most complicated AR. On occasion, I add a bi-pod as an accessory as well which I couple with a 1.5-5x scope for certain fun filled activites. I do think rather highly of Magpul P-Mags as well.

The AR based piston system is a nice design, but honestly, I have really never had a problem with the standard system. The gas tube can be a pain to remove on a used rifle, but most people never do that.

The newer ACR styles carbines are neat looking, but for my civilian purposes, a basic A3 16" barreled AR has performed very well for me and at their price, I will pass for now.

The top rifle is a 20" HBAR - a too heavy for carrying around all day. The middle rifle is what I use most and my favored configuration. The bottom rifle is for longer distance fun more precise shooting.