I've tried the archers a bit because I adore the models but I have never, ever done anything useful with them. At most I've found they cause a couple of wounds and are then killed at long range or just melee to death. I've tried cover, I've tried the upgrade. Nothing has ever worked.
The Katanaka sniper on the other hand has brought me nothing but goodness. I've had them drop a guild guard or two with critical strike, or tie up board area's with aggressive From the Shadow's deployment or be well placed for schemes or scheme markers. They are the same price but can just do more things better. I really wish the archers were viable but I find like a lot of the early TT stuff, they aren't.