When Barrett submitted their MRAD for testing in the Precision Sniper Rifle (PSR) trials, it was wearing a Thunder Beast. Surefire has a good muzzle brake attachment that has very little impact on accuracy. I've got 3 AAC cans, and I'm pretty happy with them. Prior to December, it took 5 months to get a tax stamp. I've got my fingers crossed on what's in process now.
If you want a can that will last a long time and is easier to carry, get a titanium. You'll appreciate the lighter weight if you have to carry it very far.