In my mind, these are the basic Troops choice of the Eldar army. They got much better in this edition, picking up an extra point of WS, BS, and I as well as Bladestorm on their shuriken catapults for only one extra point per model. They can still take a heavy weapon platform for a reasonable price (except for the missile launcher, which is very expensive), but the platform benefits from Battle Focus now. Finally, they are one of the units that can have an attached Warlock, who can bring some useful psychic powers. Overall, they’re a solid unit with good offensive output at close range.
Guardian Defenders do have the downside of short range, so anything that survives their shooting will probably rapid fire or assault them next turn. Even with Battle Focus, they’ll have a tough time escaping, so Defenders tend to be very suicidal when they take the offensive.
If you take away a Guardian Defender’s shuriken catapult and give him a pistol and a sword, you get a Storm Guardian. Looking at their statline, it’s obvious they won’t defeat many units in assault. Their real advantage is that they can take two flamers or fusion guns in a squad, giving you special weapons access on a bargain unit. I’m still not a huge fan, as you can get a minimum squad of Fire Dragons for the same points as a minimum squad of Storm Guardians with 2 fusion guns, but the Fire Dragons have 5 fusion guns. Sure the Storm Guardians have twice as many wounds, but the Fire Dragons have double the armor save, so they’re just as durable against weapons that don’t pierce their armor (and most weapons will go through Storm Guardian armor anyway).
Dire Avengers are essentially elite Guardian Defenders. They have the same stats except for an extra point of LD, and they have a 4+ save. In addition, their shuriken catapults have an 18” range, allowing them to stay out of assault range and rapid fire range of their targets much better than Guardians. They also have Counter-attack, but they’re not very good in combat so I don’t expect that to make much of a difference.
Dire Avengers can take an exarch, who has an extra point of WS, BS, I, A, and 3+ armor save. Not a bad upgrade considering Space Marine Sergeants cost just as much to upgrade and only come with an extra attack and point of LD. He can take a twin-linked catapult (which won’t do much since he’s BS5), a power weapon, a diresword (which is an AP2 power weapon that can remove a wounded enemy from play), or a power weapon and shimmer shield (which gives the entire unit a 5+ invulnerable save).
For exarch powers, he can take Disarming Strike (removing a special melee weapon from an opponent in a challenge 72% of the time against lower WS opponents), Shield of Grace (giving him a 3+ invulnerable save in a challenge but reducing him to a single attack), or Battle Fortune (giving him a 4+ invulnerable save). All of these are really only useful if you get the squad in combat, which is not what they’re good at.
In all honesty, the Exarch doesn’t add much to a shooty Avengers squad. Only the twin-linked catapult adds anything to the squad’s shooting ability (and not very much). In most cases, you’ll be better off just taking standard Dire Avengers without an Exarch. If you want to take an Exarch (and they’re a cool idea, so I will if I have any spare points), I would suggest a few builds.
An Exarch with a twin-linked catapult and Shield of Grace shoots well and makes a good tarpit in assault. It doesn’t matter that he can only attack once, since his attacks aren’t likely to kill much. If you actually want to kill something, I vote for a diresword and Disarming Strike. High initiative AP2 attacks are pretty scary, and he’ll be able to disarm his opponents most of the time so he won’t need an invulnerable save. Finally, if you just want to make your squad more durable, take a shimmershield.
So which one is best to put in a Wave Serpent?
Cramming as many Wave Serpents as possible into a list is quite popular, and for good reason. Guardians and Dire Avengers are popular choices, since they allow you to take Wave Serpents in Troop slots. As you may have guessed, I’m not a fan of Storm Guardians so that leaves Defenders and Avengers.
Defenders have the same damage output as Avengers for fewer points, so they are tempting in that regard. However, their lower armor and range make them much less survivable. They will do the same damage when they disembark, but Avengers are far more able to avoid and survive any return fire. In this case, neither option is better. If you want to save the squad until the end of the game to finish off weakened enemy units, Defenders make the most sense. If you intend to deploy the squad early to kill and kite with enemy infantry, Dire Avengers will do a better job.
It’s also worth noting that if you just want to take a Wave Serpent as cheaply as possible, a minimum squad of 5 Dire Avengers is cheaper than a minimum squad of 10 Guardian Defenders.
Note: I’ve heard a few people talking about putting a Defender squad with a Warlock with Conceal in a Wave Serpent. The idea is to cast Conceal to improve the Wave Serpent’s Jink save. Looking at the effects of Conceal, it only gives the Warlock Shrouded. Therefore, it provides no benefit to the transport he’s riding in.