I always liked Dog mode more than God mode, as it could kill everyone in a certain radius, totally ignoring walls. The God mode shots could be avoided in an area with a lot of walls. That, and in Dog mode you could crawl through any opening, and sneak up to someone and bite them to death (as it was also the fastest no one could get away).
ROTT's Dog mode was the reason I've played FPS-es as Dog ever since.