The White Scars section of Kauyon includes four new Formations. Most importantly, for me at least, these Formation can be taken with an Chapter Tactics. These are part of the Scarblade Strike Force, but can also be taken by any Space Marine army (or allied into another force). However, they can't be taken as part of the Gladius Strike Force.
Stormlance Battle Demi-Company
The Stormlance Battle Demi-Company is very similar to the standard Battle Demi-Company, containing a Captain or Chaplain, an optional Command Squad, 3 Tactical squads, a Devastator squad, and either an Assault squad, Bike squad, Attack Bike squad, or a Land Speeder. The only option it really loses is the ability to take Centurions. It does have the restriction that all non-vehicle units must be equipped with jump packs, bikes, or a Rhino or Razorback.
The Formation has two special rules. The first is Clean and Sweep, which allows the whole Formation to re-roll failed to hit rolls when targeting enemy units holding an Objective. Obviously, this is pretty handy as holding Objectives is what win most games. Second, and much more fun, is Mobile Firebase. This makes your Space Marines into Eldar-light, allowing them to move D6" after they shoot, and 2D6" in the case of bikes and jump infantry. If the unit makes it completely within 2" of an access point of their Dedicated Transport, they can get back onto it, even if they disembarked in the same turn. The only restriction are that units that make these extra moves can't assault that turn.
Combine the movement after shooting with Hit and Run, and you get the most slippery Space Marine force available. It will be incredibly hard to pin down, and even target, as your squads can easily jump out of their transports, shoot at full effect, and jump back into their transports. No more shooting out of the top hatch of the Rhino for you.
While the Stormlance certainly fits very well with White Scars Chapter Tactics, it can definitely work well with the other Chapter Tactics. Re-rolls to hit important enemy units along with the ability to jump out and back into your transports are helpful no matter what Chapter Tactics you use.
If you want more bikes in your army than the Stormlance Battle Demi-Company can provide, then the Hunting Force is for you. It contains a Captain, an optional Chaplain and Command Squad, 2-5 Bike squads, 1-3 Attack Bike squads, and 1-3 Scout Bike squads. Every model must be equipped with a bike. Just based on the units taken, this Formation is perfect for White Scars. It helps that it's a core choice for the Scarblade Strike Force.
The Hunters' Prey allows the Formation to pick an enemy HQ unit as its primary target, while two other units are chosen as secondary and tertiary targets, at the beginning of the game. The whole Formation gets re-rolls to hit and to wound against the primary target with any attacks. They also gain Furious Charge against the primary target. Once the primary target is destroyed, these abilities transfer to the secondary target, and then the tertiary target. While restricted to a single enemy unit at a time, these are really good bonuses, and every unit in this Formation has the reach necessary to attack their designated target.
In addition (not that I think this Formation needs anything else), the Formation gains Thunderous Assault. As long as they are in a unit with at least 5 models, each model inflicts 2 Hammer of Wrath hits. That's not bad at all, especially when paired with all the White Scar and Scarblade bonuses to Hammer of Wrath hits. When part of the Scarblade, models in this Formation inflict 2 S5 automatic hits with re-rolls to wound on the charge, along with their normal attacks. That's the sort of damage that Blood Angels wish they could dish out.
Honestly, I'm not sure how this Formation would work for other Chapter Tactics. The units included are always good, but they're so much stronger with White Scars Chapter Tactics that I don't expect to see a Hunting Force using other Chapter Tactics.
The Stormbringer Squadron consists of 1-3 Land Speeder Squadrons and 1-3 Scout Squads, all mounted in Land Speeder Storms. This makes it a very simple Formation to include in any army.
The Formation gains Locate and Secure, which gives the Scout squads (but not their attached Storms) Objective Secured. It's always nice to be able to pick up Objective Secured outside of a Combined Arms Detachment, so this is a good way to cheaply add such units to your army. Outrider Support gives Land Speeder Storms +1 to their Jink saves when within 6" of one of the Land Speeders from this formation. Better Jinks are always nice, though this will likely mean that you'll have to keep your Land Speeders further forward than you otherwise would, so arm them accordingly. Finally, Rapid Deployment allows the Scouts to disembark from the Storms after they've moved up to 12". Given that Storms are Open-topped, this means that the Scouts have a massive range (with a 18+2D6" assault distance).
I think the Stormbringer Squadron will work extremely well across any of the Chapter Tactics. It supplies some durable and fast Objective Secured units that really aren't dependent on any Chapter Tactics to do what they need to do. Honestly, the standard Land Speeders don't really add that much to the Formation, so I would keep them to a minimum (armed with close-ranged weapons) and focus on the Scouts and Storms.
The Speartip Strike is composed of 1-3 Land Speeder squadrons and 2 units of either Bike squads, Attack Bike squads, or Scout Bike squads (there's a theme running through these Formations, if you hadn't noticed). This makes it a relatively simple Formation to include.
The Speartip Strike has the fittingly named Strategic Spearhead. At the beginning of your shooting phase, you can choose either Focused Suppression or Harassing Fire. Focused Suppression means that a single enemy unit targeted by 2 or more units in this Formation must take a Pinning test. For each unit from the Formation that fires at the target beyond the first 2, the targeted unit subtracts 2 from its LD. If you take all 3 Land Speeder squadrons, you can force a Pinning test at -6 LD, which is extremely reliable.
Harassing Fire forces any unit that takes an unsaved wound from any unit in this Formation to take a Leadership test. If it fails, it can either Go to Ground or be forced to move as far as possible toward the nearest unit in the Formation in its next movement phase. This is an extremely rare example of an ability that allows you to draw the enemy out of position, and will synergize well with your other units, whether they need to draw the enemy closer to assault them or just pull the enemy out of cover to shoot them.
The Speartip Strike definitely benefits from the White Scar Chapter Tactics, but it doesn't require so many Bikes that it can't work well without them. If you want to frustrate your enemy by forcing his units to do things that you want, this is a great Formation for you. It will take some skill to get the most use out of it, but with practice it could be devastating.