Like many people, I've been trying to decipher the riddle of Chaos Marine troops, and I keep vacillating between Cultists, Chaos Marines, and Noise Marines. Looking again at the core of my list right now, I've got:
HQ: Chaos Lord w/Mark of Slaanesh, Aura of Dark Glory, Power Sword, Chaos Bike, Veterans of the Long War - 135
Troops: 9 Noise Marines w/8 Sonic Blasters, 1 Blastmaster; Noise Champion - 234
Troops: 9 Noise Marines w/8 Sonic Blasters, 1 Blastmaster; Noise Champion - 234
Fast Attack: 4 Chaos Bikers w/Mark of Slaanesh, Icon of Excess, 2 Meltaguns,Veterans of the Long War; Biker Champion - 180
Heavy Support: 4 Chaos Havocs w/4 Autocannons, Veterans of the Long War; Aspiring Champion - 120
Fortification: Aegis Defense Line w/Quad Gun - 100
Obviously, I've got a couple of troops choices, and they're dedicated shooty units. I've got a Fast assault unit and a Heavy shooty unit, but I think I need a bit more assault capability there. I'd been leaning towards an assault-focused Marine squad (either Noise Marines or Slaanesh-marked Chaos Marines), but I'm just not entirely sold on one. They're not bad by any means - they're fast to strike, tough as any marine, have grenades, and have Feel No Pain - but they're still just marines in combat. Chaos Marines aren't fearless, Noise Marines are more expensive and less flexible in equipment (but can bring a Doom Siren), and both are stuck foot-slogging across the table and can fail charges as easily as any other non-Fleet unit. Also, running them in larger units - a requirement for those armies that want to assault when Combat Squads aren't an option - gets prohibitively expensive very quickly. So, what am I left with? Let's look at Cultists.
Cultists have two things going for them. First, they're very, very inexpensive. 10 Cultists, including a champion, only cost 50 points before any upgrades. Second, they can be taken in large numbers - up to 35 models per unit. After that, though, they start falling apart quickly. They're frail, weak, not terribly skilled, and have a poor Leadership score. Using them as an assault unit means trying to bounce them from cover to cover, hoping that they don't get taken apart by gunfire along the way. They will get taken apart, too; a low toughness and nearly useless armor save combine to ensure they'll die in droves, giving them more opportunities to break. If they do manage to arrive, they still have the issues of making the assault that the Marines do. They don't even have any chance to damage vehicles, so they're really no threat to much of anything other than small isolated units. That's not to say they're useless, though. I like the idea of them being a counter-assault unit, something that can use their numbers defensively to sit in cover on an objective and make life difficult for anything that wants to charge in. That's why I like the autogun/Mark of Slaanesh combo - it pumps out lots of shots, even moreso in overwatch, and can answer an assault at the same time as a standard MEQ unit.
I still don't have my assault unit, though, and while there's some good Elite choices, I still want something that can be scoring, and I want it to be thematic. To that end, I started looking at the Daemons codex and Daemonettes. I happen to have 10 painted up, and another 30 primed and ready to go, so it's an easy add-in to my army model-wise. I would have to add in an HQ since it's an allied detachment, but I've got a couple of models to use as Heralds as well. While the Daemonettes aren't necessarily tougher than Cultists - they're both toughness 3 - they're definitely less fragile. They've got the 5+ invulnerable save, which means they won't auto-die to every weapon in the game, and even if they do take casualties, they're Fearless, which ensures that they won't break and run. As far as getting into assault, they're Fleet, which gives them a huge advantage over every other assault-focused troop choice I can run; I can all but guarantee they'll make the charge. They strike before most other units, have grenades to ensure that they act at initiative, have 4 attacks each on the charge, and have rending, ensuring that they're a threat to everything. The Herald is no slouch, either, as she'll have an extra attack and Transfixing Gaze (because why wouldn't you spend the 5 points on it) to ensure she has the upper hand in challenges. Add in Eternal Warrior to ensure she can't get one-shotted, and you've got a unit that can hunt characters, squads, and vehicles equally well.
So, how many? I'm thinking 17 Daemonettes and the Herald. It's a good-sized blob squad, which you'll want for assault; these units aren't tough enough to run as MSU assault squads. 18 is three times 6, which makes it nicely fluffy, and gives you enough points left over to throw some upgrades around your army. If fluff isn't important, you can go with 15 or 20, but I wouldn't go much less than that. Since the squad is Fearless, you don't have to worry about gaming the 25% casualty point, and with their invulnerable save being the same as most pieces of cover, you can just run them out in the open (although I would try to use LoS-blocking terrain to keep them out of too many firing lanes). If you absolutely wanted to double-up on squads, you could try two Heralds (since you can fit 2 in the HQ slot) and two 8-man Daemonette squads, but I think they'd be too fragile to make it to combat safely. If you'd rather have the ability to move enemy units around, the Masque is an attractive choice, with her 3++ save and triple Pavane, but the lack of Transfixing Gaze makes her a little weaker in challenges, so for now I'm going to stick with the Herald and maybe sub in the Masque later to try things out.
So, what does my list look like now? With the new additions, and some points thrown around for upgrades, I'm looking at something like this:
HQ: Chaos Lord w/Mark of Slaanesh, Sigil of Corruption, Power Sword, Chaos Bike, Veterans of the Long War - 145
Troops: 9 Noise Marines w/8 Sonic Blasters, 1 Blastmaster; Noise Champion - 234
Troops: 9 Noise Marines w/8 Sonic Blasters, 1 Blastmaster; Noise Champion - 234
Troops: 24 Cultists w/22 Autoguns, 2 Flamers, Mark of Slaanesh; Cultist Champion - 167
Fast Attack: 4 Chaos Bikers w/Mark of Slaanesh, Icon of Excess, 2 Meltaguns,Veterans of the Long War; Biker Champion w/Combi-Melta, Meltabombs - 195
Heavy Support: 4 Chaos Havocs w/4 Autocannons, Mark of Slaanesh, Veterans of the Long War; Aspiring Champion - 130
Fortification: Aegis Defense Line w/Quad Gun - 100
HQ: Herald of Slaanesh w/Transfixing Gaze - 55
Troops: 17 Daemonettes of Slaanesh - 238
The plan for the army is simple: the Noise Marines soften up infantry, while Havocs, manning the Quad-Gun, handle vehicles. The Bikes pull double-duty, hunting down vehicles and tougher infantry. The Cultists stay behind the line and hold a point. While all this goes on, the Daemons drop in and chase after any target of opportunity and harass the enemy's back lines. How well this will play out, we'll see. I'll experiment with this, and other variants. Perhaps two smaller Cultist squads, or Marines instead of Daemonettes. For now, though, this looks to be an interesting list to try out.