Dark Heresy has probably been around long enough for the gaming community to recognize the setting, and the rules are a pretty straightforward percentile affair, with customizable archetypes being used for character generation. The art looks quite impressive, and it's got a very large page count for it's background. I do feel that there isn't enough support for a GM to run it without supplements, however, and actually feel that some of the editing (in terms of what to include) could have been organized better. Moreover, later 40K games have formatted themselves better, and are a lot more streamlined in the presentation of their rules. The file itself is enormous, which can lead to some technical issues in downloading. Although the basic premise is eminently workable, it currently ranks as the weakest of the 40KRP game line because of these reasons - and certainly deserves an updated edition, in my view.
[3 of 5 Stars!]