There are things server has unique qualities.

If you like graphics, like totally, iClassic.
If you like contents, iEra.
If you want cheap and balanced guns, iZone.
If you want western with crafting, iOl' West.
If you want magic/sorcery, Delteria.
If you like different graphics, GKingdom.
If you want originality and good story, GtA (Graal the Adventure)
If you want different kind of magic with a hinch of class, Zodiac.
If you like events and gralats, Unholy Nation.
If you want tons of balancing, Era PC.

Every server has its own unique quality.