My only question how does it stack up to Reaping Strike? With a one handed weapon Brash is obviously better, but with a THW what normally comes out on top?
Honestly, I like the "down" side of Brash Strike a lot. Creating a perceived opening for a monster makes that monster more likely to attack your Fighter. Your Fighter's primary job is to draw attacks from monsters. A walking wall of steel that monsters can't hit doesn't accomplish this goal against anything but the most mindless of opponents.
My only question how does it stack up to Reaping Strike? With a one handed weapon Brash is obviously better, but with a THW what normally comes out on top?
Brash Strike comes out better every time. The +2 to hit alone would not be enough to tip the balance in its favor, but adding Constitution modifier to damage makes a significant enough difference, as long as the modifier is +2 or higher.