Last night I took possession of "The Radical's Handbook", a sourcebook for Dark Heresy and essentially for Rogue Trader.
The Dark Heresy game and sourcebooks are what Games Workshop should have done with Inquisitor. That and Inquisitor should have been for 28mm not 40mm (is that right?).
I really enjoy the background information that has been developed for the Calaxis Sector. I ran the first part of the Harlock Legacy, and have found the adventures to be a great read. I am waiting for the second book to arrive before I continue on with the adventure.
I've got the Rogue Trader game and was dissappointed in the book. In my opinion it should have been a sourcebook to address the Rogue Trader Letters of Marque rather than a seperate RPG book. Nevertheless the book has been a good read, even with the inevitable double-ups from Dark Heresy.
Certainly the RPG is a great enhancement for 40K.