Crucial for melee fighters - keep activated at all times.
Bronze: Premonition, with the extra attack value a player will hit hit more often, significantly increasing steady damage output (DPS).
Silver: Drill, without this, a player's other Combat Arts may be significantly crippled regarding regeneration time if this Combat Art is raised to high level.
Gold: Idol should be chosen if playing with others, Retaliation if not. The low chance of the retaliation limits it's usefulness, but if a player is not playing with others Idol may be useless.
Note that, like all CA's in the Exalted Warrior aspect, casting speed is determined by weapon speed, and can be boosted by weapon lore skills and +% attack speed. Likewise, the casting speed will be penalized by wielding a weapon with too high a level. Even so, casting speed is probably not very important if Battle Stance is not going to be recast often or cast in battle.
Note: In the console version, this Buff will create issues with scrolling in the Bonus Overview. The issues disappear when the Buff is deactivated.
Pros and Cons
Increased overall combat skill
Without Drill, the regeneration for all other Combat Arts will be significantly lengthened.
Attack value is increased by 25 + 5*Combat Art - Level percent and 37.5 + 7.5*Combat Art - Level percent with Premonition.
Defense value is increased by 25 + 5*Combat Art - Level percent.
Weapon damage modifier is increased by 10 + 2*Combat Art - Level percentage points.