Considering adding another AR to my arsenal. I plan to assemble this one based on the info from this excellent forum.
My question is whether to go with a piston system or another gas? Direct gas is definitely less money, which means more to spend on upgrades. 
If a gas system, which is a smoother shooter - midlength or carbine?
I plan to make this my go-to gun for 3gun and training classes.
Thanks for the advice.
