Marine codex 'review' (#7): the emperor's finest

Terminators: good.

In many ways, terminators epitomize the marine nature - that of being expensive, reliable generalists, with a handy focus against infantry.

The big question, the one that's always going to be asked first, is: "Are terminators worth their huge cost?"
40 points apiece sure isn't light. After all, this is as much as a razorback, or almost a third of a naked sternguard squad.

Popular consensus - and forumitis - suggests that terminators are overpriced, and no longer fill a useful role. Popular consensus would also have you believe that mister Kantor is one of only two ways to make marines competitive, and that sternguard are 'no better than tacticals, because they still die as quickly as them,' so we're gonna ignore it.
Fact of the matter is, those 40 points buy you a lot more than they do for other armies. A terminator comes stock with 2+/5++, stormbolter, sergeant statline, and a powerfist. Not many units in the game get that, even if they splash more points (blinged tyranid warriors, nobz).

All things considered, 40 points for this isn't that big a deal, but what is a big deal is whether or not your army needs the game's ultimate generalists, and can spare elite slots on them.
Shockingly enough, the answer is often a big 'yes, indeed.'

Terminators are very difficult to shift, requiring lots of anti-tank guns to reliably take off, or massed amounts of small-arms.
Many armies have problems putting enough wounds on terminators to ensure they go away in a shooting phase, and even a small squad is going to stomp most targets flat if it reaches its destination.
Unlike other infantry at your disposal, terminators don't require a transport, move and fire at full effect, and beat up stuff just fine in combat. Because of this, they'll always have something to do, and only ever stop having an effect on battles once the squad's been completely and utterly destroyed.

Option-wise, you don't have a lot to pick between, but what you do get is kinda big.
Powerfists can be exchanged for chainfists, and one guy can take an assaultcannon, cyclone launcher, or a heavy flamer. Should you invest in 5 extra terminators, you can take another big gun.
Heavy flamers are very cheap, but since terminators only move 6 inches a turn, they don't make good platforms for these, plus needing 10 men for two is generally bad. There's also the fact that you're paying a premium for a unit that's supposed to be firing every turn, not turn 3 at the earliest.
The assaultcannon turns the squad into a decent anti-tank unit, is the same range as the stormbolters, and helps scythe down infantry at a very fast rate. Effective and solid in general, but knee-jerk reactions to its 4th edition glory have rendered it expensive.
Cyclones are what they are: two shot missile launchers. Frag or krak, obviously enough. For one reason or another, this thing has sucked since 3rd edition, but is now very good. So good, in fact, it should be your primary choice. Unfortunately, unless you started marines in 5th edition, you aren't likely to own the pieces necessary to create krak- and frag missile-spamming terminators.
In addition to this, one terminator squad gets to field a land raider as its dedicated transport. Yes, 'raiders that don't use up predator slots. Sometimes handy - most of the time, not so much.

Because of what they are (reliable, well-protected, constantly moving infantrymen, that happen to be relentless, and carry anti-chump guns in general), terminator squads are the army's best platform for assaultcannons.
Terminators happen to be the primary source of chainfists, too - a weapon that used to be very useful and necessary, but the need for it's greatly diminished in 5th edition.

Default terminator squad is 3 regular terminators, a power sword sergeant (sir 'spare wound for the assaultcannon'), and a terminator with assaultcannon and chainfist. Yes, you know this to be true. It's okay.
This clocks in at 235 points, and it takes a silly amount of firepower to remove the whole squad in one turn of shooting - more so than most people are willing to commit.
Remember, the more anti-tank that's thrown the terminators' way, the happier your armor becomes.
Like everything else in your army, you want saturation. Never take small units. Make them large, then combat squad instead. This gives you more elite slots to play with, and fewer sir SWFTAC.

Also, consider the terminators' combat presence.
Your powerfists make you dangerous to 'hard' targets, and will instant-kill most of them. Armor is really not a problem for terminators, either, and your nature makes it challenging to remove the squad up close with grunts - requiring specialists or enemy elite infantry to deal with.
Yes, people will point and say their elite infantry doesn't sweat terminators, but the truth is, they do. Unless you can torrent them away safely, something more expensive than the terminators (every other unit of elite infantry, ever) is going to die.

"But what about deep strike!" It's bad. Don't use it. That's not good enough of an answer?
Fine.
You're a shooting unit, so coming in turn two at best isn't good or smart. Not only does this mean less shooting for you, but less dakka thrown at the terminators, so more against your armor. No, keeping at least 10% of your army's points off the table doesn't 'catch anyone by surprise.'

In all honesty, and all things considered, the one thing keeping terminators away from greatness is the competition, and being able to sweep beaten enemies.

What makes it good: very durable and killy. Almost flawlessly reliable. Is an actual combat unit. Terminators are the middle ground between sternguard and assault terminators, capable at both combat and shooting, but focusing on neither.

What makes it bad: expensive. Arbitrary ten-man restriction on heavy weapons make the squad much less useful. The addition of combat squads make this a bit easier to deal with.

-

Assault terminators: great.

There are not ordinary terminators, no! For these are assault terminators - the gold standard all combat units are measured against, and the finest of the finest - for the points.
This far into 5th edition, and for the price, there are no comers.

Options first, to get the boring stuff out of the way.
One squad of assault terminators can run a land raider as a dedicated transport. Good? Bad? Mostly good.
Claws: these give more attacks, failed wound re-rolls, and that's all. "HOW CAN YOU SAY THAT'S ALL!? ARE YOU MAD!?" Next up...
Hammer and shield: congratulations. Your terminator has ascended, and is now a super saiyan terminator. Hammer and shield give these powers; strength 8, 3++ (the new black!), and anything wounded by your hammers - as opposed to 'outright killed' - becomes initiative 1 for the next turn. This is the combo you want. This is the gear tha matters, that's important, and puts the fear in the opponent. Pretend the claws don't exist, alright? Good.

Oh, and all your combat attacks, regardless of weapons, ignore armor saves.

So, assault terminators. What's there to say?
They beat face on anything - in particular, very heavy armor, elite infantry, and all monsters ever, no matter how large or small - and take ridiculous amounts of punishment to down.

"Deep strike them? Pleaaaaaaaaaaaaaaaaaase, mister VT2, madam/sir?" Yes.
But that's plan B.

"What's plan A?"
Assault terminators, henceforth known as hammernators, have a serious issue: speed.
6 inches a turn, even with the d6 from run, isn't enough to get them anywhere. Being shot at isn't nice, either.

Plan A is: "stuff 5 to 8 hammernators a inside land raider crusader. The Crusader will now drive towards the enemy, tossing out lots of firepower while doing so, and, before long, the crusader will deliver hammernator death straight into the opponent's lines."
A moment passes, then the elite-infantry unit you charged will explode into little pieces.
That's plan A.

Deep striking is plan B, and it sucks. Relying on deep strike is bad, bad, bad - almost Chronus levels of bad.
Plan B: "hammernators sit in reserve, and there are empty beacon 'pods dropped near the opponent's elite-infantry." Tigurius elevates plan B to 'might just work.'

Plan B should only be considered if you don't own any crusaders.
It's no secret that hammernators demand a 250 points crusader tax, or the squad won't serve you at peak efficiency.

Regardless, anything hammernators engage in combat will die - instantly, or over several brutal turns of horrible slaughter.
By far the finest combat unit available in the book - if not the game as a whole.

Adding Vulkan to the army makes this unit even more mindblowingly awesome.

What makes it good: with a crusader, lots of hammertime will be had by all your opponent's units. Destroys most targets on the charge.

What makes it bad: costly, extremely so. Pay the land raider crusader tax of 250, or they won't get to do much stabby, and there's not likely to be any hammertime.