I played the Demo, of course, and after that I was not sure what to think of the game. Now having had some more hands-on time I can say that I am enjoying myself immensely. The only downside is that you are running around as a member of Games Workshop's default Marine Chapter the Ultramarines.
The fanboy in me is revelling in the fact that you are actually walking through a setting of which I have read so much over the years. Moreso than any other 40K game I find myself exploring any nook and cranny and taking notice of level design and architecture. So many places to look, so many ideas yet to be recreated as scenery.
If you are into 40K and the Imperium of Man, I can highly recommend this to everyone. If not to be inspired then just to breathe in the atmosphere.
All Hail the Emperor!
*And yes I am aware this isn't related to any of my armies or miniatures....but it is 40K so there.