I was faced with this same quandary several months ago. In the end I dropped the idea of a AR10 and went with a M1A as they both shoot .308 or 7.62. In the end I went with the M1A. However, I quickly learned that M1A's are as expensive as Jeeps when it comes to modifications. Overall I am happy with the decision I made.
2012 JKU Sport, Rock Krawler 2.5 Flex, Smittybilt SRC Side Armor, Mesh Grille MOD, Sony Double DIN AV Receiver, Back up Camera, Kicker Speaker Upgrade, ARB Twin Compressor, Dominion Off Road High Lift Mount, Homemade Paracord Grab Handles, Nitto Trail Grapplers, Paramount Rear Bumper with Tire Carrier, KC Hilites Daylighters, under seat lock box, Metal Cloak Front Bumper, BARTACT Seat Covers, BARTACT Sun Shade, x20 Comp Winch, sPOD, ARB Air lockers, 4.10 Gears.