i guess the question is, do you want 5 extra attacks or a 6+ ward save. against a weak foe, the extra attacks are always better, while against a strong foe the added defensive bonus may be more useful. however, no matter which enemy you're facing, the goal is to win combat... and to that end i think spears are more effective. i have 4 units of saurus in my army and 3 are equipped with spears, and 1 with hand weapons. in the future, any more saurus i get will also probably have spears.