Party Powers

Glevel 1 - Bloodrush
Bloodrush  is not unlike jedi dissipate attack. Damage is amplified for a number of rounds. It is limited to a number of uses per merge, so it isn't useful except in emergencies.

Glevel 9 - Chain of Fate
Chain of fate makes a percent of damage hit through a stack of monsters. It isn't a large percent, but especially for large players it can add up. It will pull agro on the sii using it if the tank hasn't initiate combat yet.

Glevel 11 - Bubble
Bubble  is usable on any non-sii and it sets a one time use bubble of protection around the target set to an arbitrary number. If damage to the target (which depends on the guild to a large degree) exceeds the threshold set then the bubble pops and a substantial portion of the damage is blocked. The bubble cannot be reestablished until the next round.

Cost includes 30 sp or so to put up the bubble as well as some control to maintain. When the bubble pops, there is aditional control cost which scales in proportion to how much over the threshold the damage is. So for areas where the damage from mobs is really spikey, the sii can only block the higher end of the damage range or the efficiency of the power will drop significantly. (Note: I have never managed to die from this, but it is theoretically possible)

So, practically speaking, I start by setting this threshold high (usually 1000-2000) and dial it back down from there if the bubble is not firing often enough.

Bubble works best in areas such as Carnegie Hall v2 and Portal of Life v3 where there are occasional very large special attacks. Areas such as cubes and Mantis Swamp where the damage is very steady it is very hard to set the threshold in such a way it doesn't fire every round, which is rarely sustainable.

Glevel 11 - Mitigate
Mitigate is usable on any non-sii and "protecting them from negative energies". There are a limited number of these available per reset, but the protection is constant while it is active (10 or so rounds). The exact nature of this protection is unclear.

In theory, this protection would be more effective against mobs with constant damage and multiple attacks, assuming it is straight up damage reduction.

Glevel 14 - Mesh
Mesh greatly increases targets hp regen, on the order of 20hp or so a round.

Glevel 15 - Shock
Shock is a very random power, but very effective. It can either act like jedi mindblock, jedi confusion, or a strong fear effect purely at random.