Well the only races that I have try are the Man of the West and the Undead, and I have to say that the Undead are probably the best. I beat the whole game with them. What I did was just bought the reaper holding people, the swinging mace people, and scouts. Those were they only ones I needed. After that just improve your reaper people(sorry forgot their name) and improve the armor and speed. Forget about upgrading the swordmans, and spearmans. Just use the reaper people, and a lot of them in a group, and they're really good and effective. That's how I won.