Do any of you that have commented still play? I have been playing since 08 and I've tried other rpgs, but I always come back to Dark Heresy (and the others 40k rpgs).
The setting works too well for my tastes and interests.
I'm currently in session 65 of my campaign (Tombs and Tendrils (On Youtube).
We have had many crazy experiences with Psykers. I really like the subtle approaches the powers many of you have said, particularly swapping ammo and grenades around the team.
I have taken several liberties with some of the powers and mutations in the game, even gone as far as creating powers to better fit the narrative of the setting.
I find its never so much about what the power is so much as how they decide to use it.