A few thoughts about Righteous Fury.

Firstly I allow all my NPCs to access Righteous Fury as I find it makes every fight potentially deadly for the PC's regardless of their level (which is as it should be).

Further more both PCs and NPCs automtically pass their Righteous Fury checks (i.e a roll of a 10 automtically allows you to roll another dice) whcih again makes gun fights a lot more dangerous.

I was just wondering whether any other GMs had modified the rules in a similar way?

Well, we made another approach to make Dark Heresy more "dangerous".

For example in our group fate-points are only restored after major event in the campaign. (That can tak roughly around 5-10 sessions of 2-3 hours)

And with the current encounters we face this works pretty good. I think with general passed RF test and RF for any scum you encounter the danger of burning fate-points is just quite to high but that depends on your akolythes, their combat strenght and the encounters you made for them. Normaly our GM balances encounters with more manpower and the same intellicent tactics we use.

I agree with allowing anyone to RF but I don't let RF confirm automatically. This to me is a little too dangerous. But if your players and you like it, go for it!

I've heard from some people have replaced Righteous Fury with the 'Zealous Hatred' rules from Black Crusade . In case you are unfamiliar with that system: ZE works the same for PCs and NPCs- no comfirm roll is needed. If the ZH attack doesn't overcome Armour/Toughness, the attack does 1 automatic Wound; if the ZH inflicts at least one wound, the wounded character also suffers the result of a d5 roll on the Critical Hit tables.

The advantage to this system is that every combatant has a chance of wounding any other combatant; a character in power armour, for instance, can no longer walk through a room full of grots or nurglings knowing full well he is 100% immune to their attacks. The disadvantage is that, since most of the Crit results will be levels of Fatigue, it creates more bookeeping for the GM. I haven't used the ZH system yet (maybe next campaign…), but those who have seem to like it a lot.

My PCs still use Fury, but my NPCs [and Traps] have started using Hatred.

Its worked out very well- but my acolytes are high ranking [at Rank 7] and the Tech-priest extremely resistant, especially with the new Barrier talents from Lathe Worlds.