The math of the post I quoted reveals first strike to be most valuable to units that have a high strength ratio to the units they fight. Because they can steamroll (or brickwall, which I guess you could term the defensive equivalent). DeepO does say that first strikes are a benefit in a close fight, but it's a smaller perk than in a not-close fight. He emphasizes the greater benefit in a mismatch. Arathorn says they make the most dramatic difference in close fights. Those are differing (not to be construed "opposite") opinions.