UPDATE: It appears that nearly every issue I had identified in the past has been remedied. I haven't had the time to sit down and do a serious, comprehensive review of the final product. However, I can confirm that the vast majority of the issues that were in the book no longer exist, and the rules seem genuinely complete, with no contradictions, unanswered questions, or immersion-breaking imbalances. It's a very substantial improvement, to say the least, and I'm quite pleased to see how much more polished and professional this book feels. If there are any other errors, I haven't caught them yet, and that's exactly the way a well-done publication should be. A deep "thank you" to Cubicle 7 for taking the feedback I and others submitted to make the final version of this book as clean as it is. I can honestly say now that this is well worth every penny I'd spent on it. I imagine that the only people who would be dissatisfied with this book are those who would strongly prefer a different ruleset or simply don't enjoy the 40k universe, as it presently seems about as well-written as you could hope for. A more in-depth review will follow in the coming weeks, as my free time permits.
Before I say anything else, I want to say that I love the foundation that this core rulebook provides. As someone who is both a stickler for realism and deeply fond of elegantly simple design, there's a lot of material here that I find quite satisfying. It also contains quite a few novel solutions to problems I've had with other role-playing systems. The lore and fluff generously, painstakingly, and lovingly crafted herein is also very engrossing, meshes well with existing established canon, and otherwise "feels" very much like what you would expect from a WH40K book. In short, there's genuinely a whole lot to fall in love with, as far as this rulebook goes.
Why, then, did I rate it only two stars? Put simply: typographical errors and rules oversights.
I've purchased a number of physical rulebooks, and I can say with confidence that none of them have had nearly the number of typographical errors that I've found here. The typographical errors vary. Sometimes, a word is misspelled. Other times, similar-sounding words are interchanged. There are also several situations where simple confusion has resulted in certain terms being referenced incorrectly (i.e. the Mark of Khorne text initially refers to a +10 bonus to Strength, then references instead a +10 bonus to Perception just a little bit later in the text). Some rule text (such as the often-requested mechanics for the Recoil Glove equipment item) is missing entirely. There's even a situation where a semicolon (;) was used instead of a colon (:) when the colon was clearly intended and proper:
> "As the Gamemaster (GM), you have one of the most rewarding and important roles in the game; serving as the vital bridge between your players and the grim darkness of the 41st millennium."
The rules oversights are similarly varied. One of the more high profile issues rests with the Master Crafting system, which received a seemingly token amount of attention (i.e. a brief line of text setting the minimum cost of Master Crafted items to 500 Solars was added). There are other--more serious--issues, such as the rules for Flamers being able to turn Zones into Hazards (i.e. automatic 10 to 15 damage to all creatures in the Zone at the start of their turn), or the rules for the Psychic Static Psyker power theoretically allowing a Psyker to invisibly murder in "plain sight", so long as they only interact with their target. There are also some outright funny situations, such as Bolters having the Spread (i.e. tiny Area-of-Effect) ability whereas Flamers lack it and are effectively able to be used as precision weapons.
There's a lot to love here. But, there's also no way I can say with a straight face that this is a finished product. A detailed read will reveal that there are still many mistakes that should be rectified.
Several weeks back, I actually volunteered to contribute my substantial free time toward proofreading the entire book and submitting my findings so that these kinds of issues could be identified and remedied more quickly. I covered 36 pages (the rulebook contains 368 pages total) during my "test day", during which I sent an example of the kind of work I offered to perform. I was told that it was admirable but unnecessary, and they provided a number of reasons--including "meeting deadlines"--that they weren't able to accept my work. That was back in 12 April 2023. We are currently in 29 April 2023. No new revisions of the PDF have been released in over two weeks, nor has there been any word regarding when the next revision should drop. I'm starting to have concerns about what the final product will look like, as I ordered a physical hardcopy.
My recommendation: wait until you at least see comments on here confirming that the typos have all been cleaned up. Otherwise, I can't conscionably encourage others to purchase this when it's clear that the book still requires further proofreading.