Personally I find Wraight to be hit or miss. Battle for the Fang and Sword of Justice were good, but Sword of Vengeance felt like a chore (and many decry Blood of Asaheim though I'll reserve judgment until I've read the book myself.)
In my opinion he's more much more hit than miss.
Brotherhood of the Storm is one of the Black Library's best legion-building entries, up there with Legion and Prospero Burns. I'm a WS fan, either an AL fan nor a SW fan, but I can appreciate that all three of these works set up their respective legions very nicely.
Wrath of Iron is very good considering that the Iron Hands are a hard chapter to write about. Their bleak outlook, obsession with bionics, extreme inhumanity make them very hard to root for. Yet Wraight does quite a good job of allowing the reader to understand why the Iron Hands have such a harsh, almost monstrous attitude. Talos's Night Lords are the likeable traitors. The Iron hands are the unlikeable loyalists.
If you're cool with brutal protagonists, you'll probably enjoy Wrath of Iron as it provides an interesting character study of the Iron Hands and the story itself is quite engaging. One of the non-Astartes characters is also especially memorable: a loyalist assassin whose behaviour really makes it clear that by modern day standards, many 40K "good guys" would be considered totally evil. On top of that, the final battle was pure bada$$.
For me Black Library has three outstanding authors, Abnett, Wraight and Demski-Bowden.
Agreed. I've heard criticisms of Blood of Asaheim but they mostly centre around the novel's divergence from codex company structure. I honestly don't mind if a novel doesn't strictly follow codex if it offers an excellent, well-written story.