Marine codex 'review' (#2): HQ's.

Chapter master: bad.

Masters start out expensive, and the more things you give him, the worse the inflation gets.
Virtually identical to captains, this is the book's one and only dud unit. For a character with such an epic name, you'd expect him to be the most killy unit you could ever put on the field, but no - you get a bomb, and that's all you have over captains.

The 'bomb' is a strength 10, AP1 large blast, that your master must remain immobile in the movement phase to use, and scatters a lot. Because of this, it's a serious danger to your own army, and since the master is a combat character, you really don't want him to waste time sitting still.

Rather than doing something useful, such as allowing a single squad of terminators to count as troops, he unlocks honor guard.
This is a very expensive, small, and not that powerful combat unit, which still doesn't get a land raider transport, and lacks the flexibility of the captain's command squad. When things cost almost as much as assault terminators, yet manage to be a million times worse, you know someone screwed up somewhere. For obvious reasons, we don't talk about honor guard in public.

Options for the master are identical to the captain, and will be discussed in his entry. Overall, masters are toy units, and do little that captains can't do for less.

What makes it good: durable, even without extra gear. Can be made very killy.

What makes it bad: overpriced. Doesn't have any good passive abilities. Strictly a damage dealer, with no fun unlocks or powers. Is also quite clearly not a captain.

-

Captain: good.

Reasonably priced, and very customizable, captains are just as killy and durable as masters, yet cost 25 points less, unlock the utility command squad, and if you give him a pair of wheels, he graciously takes care of all your troop-related problems.

Like masters, captains can be made prohibitively expensive, and studded with more bling and gear than you'll ever remember to use.
This, of course, isn't a smart thing to do.

Traditionally, captains were called 'force commanders,' and outfitted with a power weapon, plasmapistol, artificer armor, and an iron halo. You know, like Sicarius.
This was the gold standard for almost seven years, and some players still take it out of habit. For better or worse, the game has moved on, and 5 armor-ignoring attacks at strength 4 is no longer considered impressive, or even all that useful.
Because 40k has shifted away from marines being ultimate badass combat monsters, you'd think captains would not be all that useful up close. Fortunately, you're very wrong.
Since Mat Ward loves you, he gave you much, much better tools than marines have traditionally had access to, and though you're still only be 3 attacks base, those 3 attacks will now hurt more than ever before, while return blows are less likely to hurt you - let alone outright kill you.

Combat is really where the captain belongs, but ranged options are cheap, powerful, and actually useful for once. Since your primary combat implements (relicblade, powerfist, thunderhammer) don't give an extra attack with a pistol, you really want your captain to lug around something shooty.

Speaking of implements, let's looks at his hurty options.
There's the usual list of bad stuff (plasmapistol, combi-plasma, jump pack, etc.) and then there's everything else, which is great to moderately useful.
Unless he's carrying a stormshield, your captain will love you if you give him a combi-melta.

140 points gets you a captain with a relicblade and combi-melta. This equals 3 armor-ignoring attacks at strength 6, and a single ballisticskill 5 melta-shot. In addition to this, he's got a fairly beefy profile, and starts out with a 4+ invulnerable save from his built-in iron halo.
This combo is called 'old faithful,' and has largely replaced the ancient 'force commander' setup.

For 140 points, there's very little to complain on.
It's often said that replacing the 'blade with a powerfist or a thunderhammer 'wastes' the captain's initiative of 5, but this is not so.
Upgrading (downgrading?) to either lets you instant-kill a lot of very annoying things - something that should not be underestimated.
While initiative 1 is normally a really bad thing, the captain has much less to worry about than other characters who do this, because he's got three wounds, weaponskill 6, and his iron halo to rely on for protection, and many of the nasty things you're gonna put him up against either have initiative 6+, or are too 'ard to fear the 'blade's strength 6.

Of course, you can tool him up with twin thunderhammers, auxiliary grenade launcher, artificer armor, meltabombs, and a jump pack if you want to. We all know this, and what a waste it is, so don't.
If old faithful's not your thing, two other valid options are terminator captain, and the much loved bikerboss.

Unlike chaos terminator lords, terminator captains are actually worth their points, being more reliable, durable, killier, and usually cheaper. However, there's a significant drawback to terminator armor: no relicblade. It could be argued that this is made up for by the chainfist, and in a sense, it kinda is.
Because your captain is smarter than Belial and all templar commanders ever, he doesn't discard his iron halo when you dress him up as a terminator. Remember this.

The bikerboss is what it sounds like - captain on a bike.
His presence unlocks bike squads of no less than five models strong as troops, which nicely solves the tactical dilemma, and opens up the possibility for an all-mounted biker army. Unlike weaksauce ravenwing, who are only worth it in one specific build, biker marines are powerful.
Since bikes are stand-off shooting units, you need to include a biker command squad (more on this later) to get the most out of his combat powers.

Default bikerboss is bike plus relicblade - 165 points total. Cheap and effective.

In addition to all his weapons and dress code, he gets some bling.
2+ armor save, 3+ invulnerable (consumes one of his two weapon slots), meltabombs, half range grenade launcher, poisoned 2+ shooting attacks with combi-, standard-, and linked bolters, and if he's not on one a bike or in terminator armor, you can give him a jump pack.
Jump pack is bad, stormshield is potent, but sacrifices shooting, and the others are good if points allow, but not mandatory picks.

"Is this thing over yet?" No.
We've still got the command squad to cover.

Essentially, the command squad is a mixed combat/shooting unit that doesn't consume elite slots.
It can be geared up for pretty much anything - including mass plasma, hardcore biker assault unit, character delivery system, midfield holder, firebase protector, tanking anvil, or a combination thereof.
Including the command squad also lets you put another rhino or razorback on the table, which is always useful, even if you have no plans on using it to transport the unit itself.

Thanks to feel no pain, the command squad is an excellent platform for plasmaguns. The fact that they can take up to four helps, too.
Bikes are an expensive upgrade, but necessary in a biker army. Without the biker command, your army will not have any serious combat units - much like ravenwing.
Stormshields are an interesting option. Unlike most other units that can pick them, the command squad doesn't trade any weapons for the shields, so it's possible to have, for instance, stormshield, thunderhammer, bike, and a plasmagun.

Default combat implement for the command should be lightning claw - this because you're likely to carry around a gun, so won't get extra attacks, and the power weapon costs the same points, yet does less.
Their flag is largely a waste of points, but a company champion is worth it if you're gearing up for combat.

All in all, any marine army benefits from the presence of a captain and his command squad. The main factor limiting their popularity is the standard points limit being largey locked at 1500 points, and the fact that there're better options. Hard to believe, yes? We'll get there.

What makes it good: durable, killy, and not that expensive for what you get. Command squad is pure utility, doesn't suck away a valuable elite slot, and happens to be the best infantry platform for massed plasmaguns in the codex. Captains solve the tactical dilemma, and unlock the biker army. Also happens to be the most killy, unnamed model you can field.

What makes it bad: easy to go overboard with bling and gear. While command squads are worth their points, it adds up quickly, and limits your army in smaller games.