Just a quick rundown of the powers I've used so far, not really sure if this will be all that useful, since you can always just look up what the powers do and probably come to the same conclusion as someone that's used them. Pretty much a case of "It does exactly what it says on the tin."
All the pools offer some smashing/lethal resistance, which is handy, and I won't talk about to save typing time. =)
Psionic Mastery:
Status protection in Indomitable Will is its favourable power for most controllers, though maybe not FF with Dispersion Bubble offering protection form some status effects.
Mental Blast is it's single target ranged attack, and there's an AoE ranged attack, Psionic Tornado, to go along side it, which does Knockdown (might be knockback though, I don't quiet remember). These attacks are very good against most foes that have a mind, I.E. not robot, or zombie friendly attacks. =/
Fire Mastery:
The most damaging of the four, fireball and fireblast + AoE mezzed mobs for some *evil* containment damage, which seems to do good damage on most foes I've hit with it, but lack in secondary effects, not always a bad thing though.
Consume is good for getting your endurance back if you're in need of some, assuming you're running Force Bubble, or Repulsion Shield when you need the end, you won't be able to have the foes close enough around you to use it though... D'oh.
Stone Mastery:
Stand out power in this set for me is Earth's Embrace, raising your amount of Hit Points for a period time/self heal with a long recharge.
There's also a single target, close range (not melee), quiet damaging, attack in Hurl Boulder, that sometimes does knockback.
There's also an AoE knockback that I've never tried, so can't really comment on, but I'd assume it's handy if you've got a tank on your team, and an aggro magnet other-wise.
Primal mastery:
Power boost is the power to look out for in this set, boost your status attacks duration for five attacks (I believe), or for twelve seconds (roughly) worth. Though with the arsenal that mind is packing in the hold/sleep/fear department, I don't think you'll need this so much, because if there's anything moving it'll soon be still. =P
I'm not sure how end heavy FF is after ED, as I've not teamed with one since then =X, but if it is end heavy conserve power might help a bit - it's a little bit like your own, personal, Recovery Aura - well actually that's pretty much what it is. Heh.
Power blast, a single target, long ranged attack, while dealing good damage, it has a high chance of knock back, which can annoy melee people, but if you pick your target well, no worries there. =)
Um, I'd personally get Fireball and Fireblast from the fire pool. Very good damage right there. Long post just to say that I'd take fire.
