First up: it's the usual nicely-produced GW hardcover. They have this figured out and it loks very much like a 9th edition codex style-wise. The grey tone throughout offset by colorful artwork and pictures of miniatures ... it looks exactly like what "9th edition 40k book" should conjure in your head if you've been keeping up with the game.
That said it is less than 100 pages and was going for 50-60 bucks most places. So it's thinner than a codex and yet costs more. It's about 40 pages of lore and background, 10 pages of pictures, roughly 20 to cover the new Boarding Action rules, then about 20 more for specific boarding action missions. I rarely bring up cost here with 40K because it's just part of the hobby - it's expensive and always has been. For someone who remembers the $22 box of 30 marines and 5 metal minis in a blister pack for 5.95 it's just part of the deal. This one though feels like a boundary-push given the size and scope and that it's supposed to be FIVE (!) books. I am assuming that the lore will progress and also that each one will contain additional rules for Boarding Party games so if you want the full scope of those it will cost 5X what any one army's codex did -and then we will turn right around into an edition change and it will all be moot anyway. In an earlier edition this would likely have been a one-off softcover supplement book for half of that price but this is where we are now.
Cost gripes aside I admit I love the Boarding Action idea. I always liked both the Space Hulk game and the concept within the setting and that seems like something that a) would be worth fighting over within the universe of 40K and b) gives an easy excuse for any number of factions to show up for a battle or a campaign regardless of location or temperament. The rules are solid and the missions are interesting enough and with a 500 point limit it does keep the games fast. I was a little disappointed at some of the restrictions, namely the lack of dreadnoughts as this seems like exactly the kind of mission where an armored walker would be desirable. Without them it's goes back to a hero-hammerish approach where characters are the heavy hitters in many cases. Sure, "no vehicles" is the simple approach but I think a few rules tweaks could have made this work well. Maybe add some of the dreadnought-sized monsters in too just to be fair.
There is more to the whole Arks movement than just these specific books. There is the latest tournament/mission pack and it seems solid enough though I've played zero games with it. The missions mostly look like refinements of the Nephilim missions as do the objectives -the big change for this season is the force org chart:
There was a lot of hubbub when this first came out but that seems to have settled down as people have embraced and begun exploring the possibilities this change offers. Sure, it might be an end-of-the-edition-take-what-you-like-blowout kind of thing but damn it looks fun. That's why we play the game, right?
So it's a mixed bag for me. I like the content but I think it's overpriced, even for GW. That said I'm probably going to buy them all because I'm a sucker for the story, especially the potential for some kind of game-changing lore of significance and the return of The Lion. I know, but that's just where I am right now.
I'll have an update looking at the Angron book soon, maybe for next Friday.