Closer to 4.5 than 4.
I've read some of the other Ork centric novels Mike has put out, and while this one is not my favorite, Warboss highlights his ability to carve humor and horror into digestible pieces.
As a narrative, I love the premise and execution with little to complain about on the technical side. There is so much to love here. The changing perspectives lend to a jazzy flow in the writing that Brooks has perfected, jumping from ork to grot to human and beyond to a seamless lurch. There are moments where we get different perspectives to the same event that often add much to big moments not unlike a heist film akin to "Snatch," so much so that now that I've made the comparison I can't stop lining the two up in my head.
In the moment to moment action, Mike delivers splendid sequences that rarely left me without a smile on my face. There is a farcical element to Orks as there should be, but despite the madcap hijinks of the various orks at play, their threat is always put into perspective by the hapless victims caught up in the stampede.
What holds this one back from being at the top of my list for warhammer fiction is that I didn't enjoy this as much as Brooks' other works, and by the end found myself unattached to the characters that he clearly intends to do...something with. There is a general linkage between this and his Blackhawk book that didn't really work for me either, but its such a small ignorable element that does not take away from the standalone nature of this novel.
That is not to say the characterization was weak--not at all--but we simply spend so much time zooming to our destination that by the time all the major krumpin' concluded I wasn't exactly keen on wanting more. I got my Ork fill for now, but I will be back! In the meantime, I plan to take a look at Mike's other work, and you should too. Guy has got the knack.
Read, or listen! While I started reading it, I took a listen to the audiobook and immediately swapped over due to the stellar narration on hand. There are some light post production flourishes that really bring it to near audio-drama status at points, but in all I would say make this your next roadtrip listen; you won't regret it.