Expert in sword gives you quicker attack, but all master does is allow you to use a one-handed sword in your left hand, so all the damage you do is limited to the capabilities built into the sword, e.g. 3d4 + 10 for a mighty broadsword. However, expert spear adds a point to your armour class for every point of skill, and master spear adds to 1 point to your damage for every point of skill, so a sacred spear in the hands of a just-promoted master does 1d9 + 13 damage inherent in the spear, plus 8 points of damage from his skill, plus another 8 points to armour class. It's a no-brainer really.
