I think the efficiency would be neutral AP wise, if you would use it with 2 AP attacks (2-hand or Dual wield). It gives 50% bonus, so you would deal 150% damage at the cost of 3 AP, 150% AP costs. Can be worth if it the damage would be enough do kill an enemie and you would not have 4 AP for two attacks. But is it worth one trait point?
Regardless I still finde sneaking during fight in most cases pretty ridiculous.
I've found this to be true for regular attacks. One also gets a stronger opening attack, which in my opinion is the biggest reason to get it.
The other big way it helps out is that it synergizes with abilities, which have cooldowns. Being able to add 50% more damage for 1 AP to something you can only do once every 3 rounds, etc. allows you to spend less time doing weaker basic attacks.
Also, the 3 cost abilities and Source point cost abilities make Guerilla efficient when using them even w/o the cooldown consideration.
Because of this, I like the Guerilla talent.
