The AAC muzzle brakes are awesome if you can get a hold of one with the 7.62 thread. The blackout is also fantastic.
Are you planning on running a can now or ever? That should be your biggest concern since most quick attach silencers use a proprietary mount (I stick with AAC so I can silence anything I want). If you're NOT planning to suppress the rifle, Noveske's flaming pig flash hider is the best thing since sliced bread imho.