This perk is one of the most helpful. But as of 1.7, the ability is broken. And by broken I mean, cheap. It seems to finish once the enemy is done swinging, which is about 15 seconds. I can shout fire, and kill the enemy even has a chance.
It's idiotic. I don't know how they managed to screw up something that random.
1.7 also has caused more stutters, and lowered framerate in some areas. And I though 1.6 was bad...