I like the Word Bearers books a fair amount. I liked the second better, as it was more intimate due to the main characters all just going on an adventure, and we see more of their various interactions and the complexities of the relationships between what were basically fairly shallow archetypes in the first novel.
There were also some nice moments, like the guy getting separated from the rest of the squad and what happens afterwards.
The third was a satisfying end, if a slight misfire in terms of the the sub-plot. And the huge battle veers into bolter-porn a little. And the little short that wraps up the fate of one of the characters was good, if dark as heck.
Also, the characters cameo (or outright appear) in various Heresy shorts.