I want an AR in 9mm, and was all set to buy one when The Madness hit. Needless to say that plan went out the window for the time being, but when it settles down I will pick one up.
My intent is to just pick up a factory built Colt model. I would assume that coming from the factory I shouldn't have any "tuning" issues, and I'm fine with Colt vs "fill in your favorite". I like the idea of a carbine that accepts ammo I already have stock of, is the same as most of my pistols, and in saner times is plentiful and cheap.
I know I know. There will be a bunch that say 9mm is a waste in a rifle, but at the ranges I would intend to use it it would certainly get the job done. In that SHTF scenario so many seem to worry about, but can't really adequately define, I don't intend to fight. I intend to run whenever possible and fight only as a last desperate resort.
That stand your ground mentality is fine and dandy if you're young, single, and full of hormones. When you've got family to worry about, fightin is the last thing I want to do.