In Only War, you are grizzled imperial guardsmen fighting the good fight, engaging in daring do in a regiment of your own creation, fighting horrific monsters and vile heretics and engaging in that jolly cameraderie of young men killing other young men. You get to see all the cool fluff of the warhammer universe, get to do more varied missions with the same amount of intrigue and interaction if that is what the party wants, all in a streamlined rules set. There are also tanks. Always a plus, in my opinion.
