Well, if you got 3 uses per day, you're done for the majority of the encounters. You can then use items, like chronocharms (not that they are reliable, but they will enable you to skirmish at least one more time).

Manyshot on the other hand, unless you find a decent way to boost your attack rolls, is not reliable. For just two attacks it requires a whooping -4 penalty on attack rolls. For the **maximum** of **four** attacks it bestows a -8 penalty on each arrow. Sometimes you are better off moving and shooting just one arrow than shooting multiple arrows.

For example:

Let's say you are a swift hunter, 3 scout/6 ranger with greater manyshot. BAB is 8, so that means just 2 arrows. Let's say you got a to hit roll of +13 (+1 bow, +1 point blank, +3 dexterity, +8 bab) and you are facing an enemy with ~25 AC. That means that if you use manyshot, you get a 25% chance to hit the target with each arrow. Average damage per hit is (let's assume average bow damage is 5) 15,5 (skirmish damage is 3d6 at this level). So, 15,5 + 15,5 = 31 if we multiply it by 0,25 (chance to hit) = 7,75. Now, the same character without manyshot has a 45% chance, which means 6,95 average damage after chance to hit is applied. As you can see, the difference between the two is less than one point of damage when you first get greater manyshot.