Yeah there is a lot of custom content in addition to what's already provided by the base game.
But to narrow it down the best I can, all you need to know is this:
-You will be capable of soloing *nearly* every vanilla instance eventually.*
-Higher drops rates. Higher exp rates.
--I personally feel this is the highlight of the servers.
-There is no Rank 9. (thank god)
-While this server serves both types of players, this is heavier on the PVP side.
-Epic Coins is this server's main form of currency.
--A decent place to farm this, IMO is the area around the Shrine of Ancestors and the Shrine of Immortals.
---Not the best place to start farming at 110. Epic coins can be gained from the boss in Phoenix Valley however.
-Standard coins are far easier to obtain than PWI. It will not take you long to become a billionaire.
-All current fashion is available, and it's far easier to dye them. None of that pack-fashion only bull****.
Your leveling options aside from the level scrolls, is Phoenix Valley, the morai dailies(all subject to the higher exp rates. Your eyeballs will pop out upon finishing something that gave you 10m exp as an example.), Old Heaven's tear(the mobs here drop mats for gear too), and I can't think of others at the moment.
*May be dependent on the class.