Something of that quality and caliber I would not run cheap ammo thru... With .308 at a +/- $1 a round if you've got $$$$ to blow thru $30-40 a magazine in under a minute I say go for it!!
LaRue, Noveske, BCM, WOA, JP, LWRC are just a few very good quality firearms mfg's
Stick to a 5.56/.223. With the proper barrel and quality ammo you can shove a round up a fleas ass at +500yds with a lil ol .22 caliber projectile.
I can't justify the price for those LaRues, some guys can. If your life depends on that rifle on a daily basis then hell yes it's justified.
If it were me I'd buy a Nice Bravo Company and do some mods to it to make it how you like it. Spend the extra $$$$ on ammo. Believe it or not AR's are very much like jeeps. They have a HUGE aftermarket following, you can make it any size, color and shape you want to make it yours. But in the end it's still an Ar15... Jeep.