Well when I was playing PvE exclusivly I chose Primal because:
1)Conserve power,end is always a problem with Ill/Storm unless you slot endred in your powers(which I do)
2)Power blast,really good damage with containment.
3)Temp Invulnerability,30 odd % S/L res when slotted.
4)Power boost,the best anc power for controllers,it boosts the secondry effects of powers such as holds,disorients,slow,sleep and stun.
Rchg aint bad and it boosts by 100%.
With PvP the best option Imo is Psionic because of Indominable will which gives res to mez and is a must for a PvPer.
I've tryed all the others but they dont even come close to the 2 i've mentioned imo.
So Primal for PvE Psionic for PvP,hope this helps 
Yep, it sure does. Cheers.
It's between Primal & Ice at the mo. I can live without Conserve Power due to the massive recharge but Power Boost looks too good to pass up.
How long is the duration on Power Boost (recharge is 60 seconds)? I assume it affects Fear & Slow effects too?
It lasts for 20 seconds and affects any secondary effects of your powers (so yes, it will affect fears and slows).
So I'm finally about to hit 41 and I was wondering which Ancillary to chose for my Illusion / Storm. We're talking PvE by the way.
I've read the other post on this but I'm still undecided. Plus its dead quiet here today so I thought I'd throw it out again.
Earth is out as it doesn't fit my char. Ditto with Fire, plus I've no decent immobilise so I won't be able to do AOE Containment + Fireballs much.
Ice is a strong contender as it blends nicely with concept and all 4 powers could supplement Carni nicely. Hibernate could be useful for those uh-oh moments when the Decoys drop and I get pasted by angry mobs, especially since I've no self-heal.
Psi is the one people advocate but I'm not convinced its much use to me. The mez protection is nice, but generally I don't attract enough attention to be mezzed.
Primal could be very useful too. Power Boost would be excellent at 47, but the other 3 powers I could take or leave.
So i'm sort of inclined towards Ice. What do people think?