I've always been curious to what extent most warbands just stay in the Ragged Helix or other sections of the Screaming Vortex and spend most of their time plundering other Chaos forces. The first campaign I ran never left the Vortex and we never ran out of interesting adversaries or story hooks. How often do other groups' head out to actually do battle with the Imperium, or other threats?
Similar, I've seen three general ways to run Black Crusade over time. Saturday Morning Cartoon Heretics, where everything's so over the top that it's really more of dark humor than anything else. Antiheroes, where the Heretics have decent reasons to hate the Imperium or have hooked up with Chaos and chronicle their slow degradation and the loss of the ideals they began with in the face of Chaos (Or perhaps, their triumph and ability to balance their goals and the demands of the Gods). Finally, there's just running it as is, as a bunch of crazy people worshipping dark gods for power. I've tended to prefer the former two, having run one of each, but I'm curious what kind of tone most people try for. Comedy? Drama? Crazy murder?