The first misson "Death beyond duty" has had my players gripped from the word go. Wow, it's perfectly captured the 40k grimdark feeling and the overall plot premise is great. I'd say my players only have a single session before we complete, but they have already asked for me to start homebrewing a follow on adventure (which depending on the choices the player take in this supplement, there's loads of avenues to go off and explore).
The first mission is a bit "on-rails" to start, as it see's players exploring a Manufacotrum. But it's a perfect introduction to the game and the 40k setting in general. Could not recommend enough!