It's also worth noting that in 3.0, PA for archers was considered a huge no-no, because archers typically had much higher attack bonuses that meleeers. In 3.5, this is less of an issue, as they don't get to stack enhancement bonuses anymore (and the Magic Weapon spells are less useful). I also think that any DM who allows archers to use a PA-like ability should pay very close attention to cover modifiers.