Edited: 1/4/2012
Quote Sins Wiki:
https://www.sinsofasolarempire.wikia.com/wiki/Discord_Battleship
A powerful warship with unique psionic abilities capable of harassing enemy ships.

Firstly i think they have changed the capital ships name to the Discord Battleship as listed on Sins wiki.
As hinted its a front line assault ship assuming the positions that radiance's take in fleet formations however i usually was under the impression the ship was a battle-cruiser due to its familiarity in its role on the battlefield to the Rapture.
Unfortunately i haven't found much use of the rapture until late mid or late game. Its unfortunate i've never had much use of it as much as i love the rapture's vertigo. The question whether this capital ship makes a difference in my opinion remains to be seen however it does shine in one thing which is it does have the same positioning and range attacks as the rapture in all regards and its first ability is very cheap to use with a fairly good cool-down:
Fracture:

Enemy frigates and capital ships within a radius of the target ship have their armor telekinetically weakened for a short period of time. Extracted from the game.
Most effective against units like long range frigates and others this ability harasses enemy units in range and weakens them. Not much is known about how this ability levels up-whether is gets stronger or lasts longer at level 2 and 3. It is by far the most game changing element for the advent play style which as always been less on the LRM spam but focused on the synergy of all units and fire-power, dispersion with malice that acts like splash damage, the energy aura from the Halcyon reducing weapon cool-down of all nearby units by a max of 22% and an effective damage increase of up to 28.2% (execept strike craft).
Where fire-power was meant to deal damage to over-come there enemies strength and vertigo would later weaken there damage output this ability now weakens even the enemy ships which brings them down a notch since advent ships are not all that buff. Is this a dangerous ability? Tell me your thoughts? As an opening capital ship it fails in that category for me and the energy aura and malice will always be openers for me simply because there ability ranges are 8000-km. It is however a dangerous ship early game -if you get a chance to build it after owning an halcyon and mother-ship then you should.
Psionic Scream:

Enemy frigates and capital ships near by target are afflicted by a powerful psionic wave dealing moderate damage and preventing them from using abilities for some time. Enemies afflicted by Fracture take bonus damage.
Should be manually cast simply because of its instant effect. It does not target all ship types which is unfortunate and the effectiveness of this ability is broad but high maintenance and high cost as you can already tell. Of course with all advent abilities this ability works well with disciples.
Lethargy:

Tricks a target enemy ship into a state of lethargy, resulting in increased weapon and ability cooldowns for a short duration.
Range:4000Effect(s):
- Ability Cooldown rate: -25% -> -33% -> -42% -> -50%
- Weapon Cooldown: -10% -> -15% -> -20% -> -25%
This ability is another 1 that has to be manually cast and is effective against capital ships but does not necessary need disciples to be present if its the only ability your going to use- do not use this ability until you have to face an enemy titan.
Revenge from Beyond:

Nearby friendly frigates become marked. When destroyed, they will deal damage to a nearby random enemy ship
Range:8500Effect(s):
This ability is unique and is left to be experienced to be judged. I'd leave this ability on Auto-cast simply because it extends the range of this capital ship but have disciples with you because as with all fourth abilities there expensive. Is it useful: Not really but yes at the same time. its complicated like all things advent: useful in a synergy and worthless alone.
Conclusion:
Ability 1 is dangerous and i don't even know what its like at level 2 and 3. It is the only reason someone could choose to open with an halcyon and Discord. It is a deadly combination of fire-power and damage effectiveness.
Closely clustered advent fleets are vulnerable to javelis splash damage but driving fleets into enemy units then autocast this ability will be a technique worthy of victory esp backed by larger numbers of defense vessels as the tight cluster invites counters into range of ability 1.
This ability creates strong openers with desciple and defense vessels simply disabling hoshikos with steal anti-matter and killing there enemies much faster. It gives you more favourable ground to deploy illuminators more comfortably and not in a rush.
good luck and don't forget to have fun.
