This is the standard run of the mill core detachment from the rulebook. Its basically what we're used to using all of these years. Its main advantage is flexibility. It gives anything that is a troop (or its transport) objective secured. Certainly useful. Its also currently the only way to field our Crusader squads.
This is the other core detachment that is available to the army. Its restrictions prevent the use of the Crusader squad, as well as our High Marshal. However, with that being said, it expands objective secured to all of the units in the detachment. It also grants the special rule tactical flexibility. If you're familiar with the Ultramarine chapter tactics, guess what? That's what it is. Cool, huh? Not exactly Black Templars...but it gives us options galore.
Anti-Air Defense Force:
This formation is useful if you need some AA. However...neither vehicle is good, so the Skyspear Auto-targetting special rule is kind of worthless in my opinion. Even if you have an additional BS 1, they are still bad. Not worth using, in my opinion. You're better off using fliers of your own to combat enemy fliers.
1st Company Task Force:
This is the veteran formation of the codex. Granted fear and fearless, it also gains Extremis Level Threat and Terrifying Proficiency. The former grants your units Preferred Enemy against a nominated unit in your opponent's army. The latter gives a negative leadership to enemy units within 12" of three units. It is one of the few ways of taking large numbers of veterans, but it is definitely an expensive formation. Nevertheless, having so many is definitely scary. However, I don't think its competitive in our current tournament formats.
Strike Force Ultra:
This formation is similar to the 1st Company Task Force, as it allows you to take a highly specialized force. However, it has the same problem: its expensive and it requires you to take quite a few things that aren't troops. There is a few fun tricks that the special rules provide you. Ultra Strike basically forces you to put the formation into reserve. Fury of the Storm allows you to add one more shot to all of your shooting the turn you deep strike or disembark from a transport the first time. Force of a Thunderbolt is similar, but it gives an additional attack in close combat the first time you disembark. Honestly? Its a fun formation, but again, the expense makes it casual in nature.
Reclusiam Command Squad:
The first of the command formations. Its basically a Chaplain and a Command squad that has the Crusader special rule, as well as a 6" Zealot bubble. No use taking this formation when you can simply take Grimaldus to do the same thing.
10th Company Task Force:
This is a formation filled with scouts. Unfortunately, the scouts do not have Objective Secured, so they are weakened because of this. They all have the Concealed Positions special rule, which grants Stealth to any model that infiltrated until it moves. This is definitely a handy tool to grant survivability to your fragile units. You also get Precision Shots your first game turn via the The Trap is Sprung formation special rule. In my opinion, this formation is worth consideration, but there are more effective uses of the points. This formation is not exactly scary. But it certainly can be an excellent distraction force for cheap.
The Storm Wing is actually useful. It allows all of your fliers to come onto the battlefield at the same time, with one roll. In addition, they gain a special rule called Strafing Run that gives the fliers BS5 against all ground-based enemy units. This is a competitive formation. Why? Because this is a configuration that you very well might take in a normal army, so there is no reason why you cannot gain special rules doing so.
Centurion Siegebreaker Cohort:
This is another expensive formation that doesn't do much for you. The first special rule, Demolition Specialist, will rarely come into effect as most tournament games will not have buildings of any consequence. Seismic Devastation is slightly more useful, as it puts wounds on units embarked in buildings or formations. However, when you are packing several Centurian squads, the Str 6 AP 4 hits are not exactly scary or needed. Maybe if they were AP 3, but not beyond that. I'll pass.
Land Raider Spearhead:
I honestly like this formation. Its a very strong tool for a rock army. The most important special rule, Armoured Behemoths, pretty much allows you to ignore all damage results on the vehicles (except explodes). The downside is this...the codex also created the Gladius Formation. Which I'll go into more detail on in a few moments. Anyway, the Gladius really puts this formation into a tough position because the Spearhead does not have Objective Secured. That puts us at a serious numerical disadvantage if facing a Gladius Formation. Thus, I'm going to say that this formation is borderline competitive, falling more on the casual side of things.
We don't use witches. Burn!
Armoured Task Force:
This formation is sort of useful in the right list. Paregoric Cant allows you to ignore Crew Shaken/Stunned results if within 6" of a techmarine. Useful. The Will of the Omnissiah gives you a +1 bonus to making Blessings of the Omnissiah repair rolls. Not useful. Overall, this formation is somewhat of a waste unless you're already taking those units in your army list. I wouldn't go out of your way to take this one, as you don't get enough in your list to warrant it.
The special rule is Datalink Telemetry and its actually pretty good. With your Land Speeders, you can grant your Whirlwinds infinite range and can re-roll the To Hit die. Minimal investment can give you very good anti-infantry capabilities. I would rate this formation competitive in the right list.
Skyhammer Annihilation Force:
This one isn't directly in the Space Marine codex, as its an exclusive web-only formation. Until the very first person buys it and then posts online what the rules are. Oh wait. Anyway...this formation is by far, the best formation I have ever seen. With special rules coming out of our ears, this formation is an Alpha Strike master. Granting you the ability to fire heavy weapons and being able to charge after deep striking is an astronomically huge advantage. Also being able to force 3D6 moral checks on your opponent despite casualty counts? Or the fact that you can get your Assault Squads rerolls to hit and wound under the correct circumstance? Yikes! This formation is nasty, nasty. Very competitive.
Gladius Strike Force Detachment:
Made up of two Demi-Battle Companies and one auxillary formation of your choice. If done so, you gain free transports for your detachment. Say what?!? Not only that, those transports are Objective Secured. Using this detachment, you can have several dozen Objective Secured units in a 1850 list. This is the revival of the razor spam list. Unfortunately, that list doesn't mesh 100% with our traditional play-style, but it definitely gains close combat mileage through our Chapter Tactics. You can also use this detachment to build your drop pod list to great effect. Free drop pods really help to be able to put lots of toys on the battlefield. Definitely competitive.
Alright, so that is it. There is a few detachments/formations that are competitive for our armies. First, the Combined Arms Detachment. This is the one we're used to using. Its also the only one we can use our Crusader squads with. The second competitive detachment is the Gladius Strike Force. This is an excellent detachment if you want to use the razorback spam or drop pod armies as it gives you free transports. Otherwise, it limits you significantly in what you can field. Probably too restrictive for other army archetypes.
As far as formations, the Skyhammer Annihilation Force comes to mind as the most competitive of the bunch. This formation is ridiculously good. Its so destructive, its gross. The Black Templars had problems with being able to Alpha Strike their opponents, but not anymore. This formation is literally perfect for us. Another formation that is highly competitive is the Storm Wing. Stormtalons are very good, especially with their points reductions, and its not too much of a stretch to take a Stormraven beyond that. Getting an extra BS is not bad, when you're not going out of your way to get it. Demi-Battle Companies are also competitive, though it requires the use of tactical squads. Giving us access to doctrines, which previously only Ultramarines had, allows us to play far more tactical games and make use of far more strategy. The last formation I'd say is slightly competitive is the Suppression Force, because it gives us good anti-infantry for minimal investment.
There you have it! The first part of my review. More to come! :D