Just curious (and this has likely been asked before and elsewhere):

What is everyone's favorite 40K RPG "system" so far and why?

What is everyone's favorite 40K RPG "game" itself and why?

I'm especially keen to hear everyone's favorite psyker system so far as well and why they like it over the others.

Kaelthas said:

Dark Heresy, it is gritty fast and unforgiving.

Game wise it is a tie between Dark Heresy and Rogue Trader, Only War has an honourable mention (I didn't play it as of yet, but I like the setting)

I liek the DH psyker system, it is like the game, unforgiving and dangerous, as it should be, not 'half power, no danger' like DW, BC and OW.

Astropath's are more 'secure' of a psyker than your regualr garden variety, so that system would be good for RT, but not for DH, OW and especially BC.

Dark Heresy has the best narrative gameplay of the lines to date.

Rogue Trader has the most immersive character, ship and dynasty etc construction i've seen - even more so than with the Regiments and characters in Only War, and i've given up hope that expansions will rectify the mess that is the Core book.

Deathwatch was too number crunching and combat heavy.

Black Crusade didn't have enough material for constructing a fully fleshed out world or running a campaign and its really hard to get a group of evil bastards to stop killing eachother and actually work collectively towards anything.

Only War has the personal combat level focus of Dark Heresy whilst feeling like it should have the Mass Combat system such as Hordes from previous lines, and needs most of the background events handwaived by the GM in order for a game to proress properly.

As such in order of preference:
Dark Heresy/Rogue Trader in joint 1st

Deathwatch in 2nd

Only War in 3rd

Black Crusade in 4th