tex, Flave, AH64 are all dead on. At $718 or anywhere near, the 6920 OEM-2 is a no-brainer.
I picked up 3 full Magpul Kryptek Highlander 6920's for $740-750 when they hit their lowest price point I'd seen in the last 10-15 years.
If you watch for sales you can get a really nice quality floating rail system for ~ $150-160, like BCM, Geissele, Troy.
Other accessories, new and used, pop up cheap every now and then, too. Stocks, backup sights, triggers, etc. I picked up 3 Daniel Defense FVG's for $8/ea a little while back.
