30K: Burning of Prospero vs. Betrayal at Calth

We've already talked about what you need to start playing 30K. Here's a tl;dr: 2x Betrayal at Calth. But now GW has released another boxed set based on the Horus Heresy, or, more precisely, the Burning of Prospero.

So how does Burning of Prospero compare to Betrayal at Calth? Which one should you get, and why?

Let's contrast and compare.

First, here's the content of one box of Betrayal at Calth (BaC):

• 2 neutral Characters
• 1 Contemptor Dreadnoughts with a choice of three weapons
• 30 Tactical Marines in MK IV armour, all of which could be armed with Bolters, plus options for three Sergeants, and a lot of special and heavy weapons (3 Missile Launchers, 3 Heavy Bolter, 3 Meltas, 3 Flamers, 3 Plasma Guns).
• 5 Terminators (Cataphractii), all with combi-bolters and power fist / chainfist, and an optional Heavy Flamer, a combi-weapon for the Sergeant, and any number could be equipped with Lightning Claws.

Now let's take a look at Burning of Prospero (BoP):

• 2 themed characters (1 Space Wolves, 1 Thousand Sons)
• 30 Tactical Marines in MK III armour, all of which could be armed with Bolters, plus options for three Sergeants, and a lot of special and heavy weapons (3 Heavy Bolter, 3 Meltas, 3 Flamers, 3 Plasma Guns).
• 5 Terminators (Tartaros), all with combi-bolters and power fist / chainfist, and an optional heavy flamer, plasma blaster or reaper autocannon, and a combi-weapon or volkite charger for the Sergeant, and any number could be equipped with lightning claws.
• 5 Adeptus Custodes with Guardian Spears or Sentinel Blades.
• 5 Sisters of Silence with Executioner greatswords, Bolters, or Flamers.

Right off the bat you'll notice that BoP is way more themed than BaC: not only are the themed characters pretty much useless for other Legions, the Adeptus Custodes and Sisters of Silence are very specific forces, and not available to traitors. So that's one point for BaC.

The Tactical Marines have more options in BaC too, if only for the Missile Launcher, the rest being more or less equal. The Terminators, on the other hand, got much more (and better?) options in BoP.

All in all, I'd say BaC is the better deal, generally speaking. Specifically, however, it depends on what Legion you're playing.

MK III Power armour is very well suited to a couple of Legions. The Death Guard, for instance, is practically known for making use of this mark. Other Legions, the more well-equipped ones like the Sons of Horus, would look better in MK IV. Additionally, BoP gets much more interesting if you're playing a Loyalist Legion, thanks to the Custodes and Sisters, who you could ally with.

Here's my advice: whichever box you choose, get at least a second one of those before getting the other one. Your force will look more cohesive, and, more importantly, you can build larger squads. If you've got good reasons to go BoP, do that; otherwise, go BaC.