The final Dark Heresy book will be vastly superior to that sample booklet. The booklet misses out about 80%(at least) of the game-play/rules/what-have-you. Dark Heresy is also going to be absolutely jam-packed with new fluff. A hell of a lot of Inquisitor players are going to be buying it just for the fluff. Dark heresy has a far greater range of archtypes than Inquisitor had in its own rulebook (tho the amount has increased drastically since, at least double, possibly triple now). and within these archtypes are lots and lots of different "career levels" as they'd be known in an RP game, giving Inquisitor players even more ideas to play with.
One of the official playtesters of Dark Heresy is a veteran member of
The Conclave and believes that everyone will be extremely happy with the end result of the book.