If only they were worth taking. Wonderful in concept, but pretty much any other unit can get a better kill count.

Yeah, but I've got a knack for making goofy units like these work, at least as entertainment. I can even attribute victories to my grotesques and rough-riders in the past.

Do you have the DE Supplement: Haemonculus Covens? If so is it worth picking up?

Without even reading it, I can tell you that it's probably not, because it's day-one DLC :V It's $50, a codex is $50, GW wants you to spend $100 to make your $50 codex work.

In a SLIGHTLY less biased tone, I can still say it probably isn't. The haemonculus units are kind of the only units in the DE codex that didn't get hit with the nerf bat (though scourges and mandrakes are apparently better), so giving them their own codex means that they probably didn't add much save for maybe the ability to take wracks as troops (which we already had, God damnit) and maybe a couple coven-specific artefacts (though I can't imagine what).

No need to worry, I agree with the over priced line of thought; it's been that way for a long time. The content of those books could have easily been put into one book. Unfortunately the 2nd SW codex added good stuff to the army, so I had to ask. I wish the carnival of pain was a viable, but with terrible saves and no volume fire, it's not worth sinking the money into it.

Personally, I'm just sticking with my 5th ed codex. My friends are pretty much in the same boat I am, so no one seems to mind.

I can't. I enjoy tournaments and such, and I don't want start getting "phantom rules syndrome" by remembering what was but isn't anymore. Some stuff I like better from before, but we have a strong gaming community here so for me it's best to stay current.

However, if you haven't tried it, Horus Heresy is pretty darned nice! Pretty much every army pulls from the same core list, making it probably one of the most balanced versions of 40k that I've seen in a long, long time.