I always use them. A few thoughts:
*They're great to deploy with your regular brigades as a rear guard with their 360 shooting to deter the other side's fliers.
*When I bring them in from the tunnels, I always do so from terrain since the board edge is often too far away to be meaningful.
*Their effect is very dependent on what your opponent does. If he's undead you can forget about -1 command to his rolls but if he parks his artilllery with their back to terrain he's in for a (hopefully, you still need to pass the command test) surprise.
*The psychological effect is problably bigger than the real one against a player who knows what he's doing.
Apologies to all female Warmaster players. I have yet to meet one of you.
Edit: mispelling