You guys are missing the point of a FH. It isn't about making the flash invisible from the targets perspective, it's about making it invisible, or at least reducing it, from the shooters perspective.
Hands down I'd take a good FH over a muzzle brake any day, or night, of the week. The reason? Because a well performing FH mitigates the flash as seen from the shooters perspective so that he should be unaware of the flash. The point being to preserve his night vision.
When shooting in low light a bright muzzle flash will render you literally blind for several seconds at least.
Which would you rather, save a split second on a follow-up shot, or actually be able to see what's going on around you and what you're shooting at?
There is a reason that most military rifles have flash hidders, after all.
IMHO, muzzle brakes are highly over rated on a semi auto rifle and seems to be the result of shooting games, and not from the real world practical side of SHTF.