Warpstone Flux Rating: ⭐️⭐️⭐️⭐️
4/5 stars. The rules are good, but there's probably only a couple of orders that you are going to take.
There are wheels within wheels, and there are orders within the Dark Angels. The Inner Circle Knights Cenobium are those orders militant within and dedicated to unique martial skills.
The plasma casters that they carry as standard are effectively flamers with breaching, but what is really cool are the standard terranic greatswords. These terminators come as standard with 2 wounds and WS=5, but the preceptor has an amazing WS=6 which blows away much of the competition.
Not only can they take the hexagrammaton upgrades, but they get their pick of Orders as well.
Augurs of Weakness: Get a bonus against AV=11 or higher. You will want Iron Wing and some hammers here. But note there are better tools in the box for tank hunting than these guys - this is a bit of a waste.
Icons of Resolve: Ld+1 when charged is not worth taking. Skip this.
Slayers of Kings: Re-rolling of 1's to hit against WS=5 or higher or in a challenge is hilarious. Take with death wing. Don't forget Terranic Greatsword bonus. Take this almost every time!
Hunters of Beasts: I'm a bit neutral on the worth of re-rolling to wound rolls of 1's against T=5 or higher. I mean, if you know you're facing lots of beasts, then yes sure. But otherwise probably not quite worth it.
Reapers of Hosts: A+1 against they have base to base contact with more than one enemy is cool. Take it if you're not wanting Slayers of Kings. Great against horde armies, of course.
Breakers of Witches: re-rolls against deamons, psykers, and corrupted is highly situational. Of course, if you know you're against daemons of the ruinstorm, it is a no-brainer. Thousand Sons will hate you for it too. As will plenty of Word Bearer armies, and certain Sons of Horus builds.
Lots of points cost here, and they can not sweep!
5 Inner Circle Knights Cenobium, 1 Legion Vexilla, Preceptor with Grenade Harness (290 points).
There's honestly not many other builds to consider. Add extra bodies to taste. Swap out a greatsword for a thunder hammer (perhaps 1 only) if desired otherwise retain those greatswords all round.