The Xin: ruthless, totally alien and unrelenting. They sport advanced technology (far more advanced than any of the existing factions) which reflects in their ships - they are tough, very well armed - but expensive to make and maintain. The Xin are meant to be defensive in nature, that is their ships and structures are geared towards dishing out massive damage and soaking up the same, but they are slow and difficult to adapt to a flexible foe. This is especially true when it comes to their home turf vs. enemy or unclaimed sectors; while they have the technology to build a sort of wormhole network between all of their owned systems which enables them to zip around pretty quickly between their worlds, their native slow sublight and phase speed means they struggle when it comes to hit and run tactics or facing down a more speedy foe.
Also, playing with the Xin you have to be careful not to suffer a catastrophic defeat, as they have smaller fleets of powerful ships which, if lost, take time to replace. Fighting on the defensive, however, the Xin excel - they are meant to very tough to root out once they've had some time to fortify a sector.
So to summarize:
-powerful vessels (roughly 2x equivalent amongst other factions, in the case of the Remnant, its 4:1 in the favor of the Xin)
-expensive to build and develop (you will need a lot of resources to run them smoothly)
-slow ship speeds both phase and sublight (painfully obvious with the mod's expanded gravity wells)
-technology allowing for extremely quick travel between owned gravity wells, does not help with sublight speed though
-cool looking ships 