The problem with the ridiculously high rate servers is that they take all of the fun out of Rappelz. By design it's supposed to be a grinder. When you hit 150 in 5 minutes and get a full set of +20 Bestial equips with 700 pets on belt, there's nothing left to do. That's typically when you get servers like Zesua and Elite who create ridiculously and stupidly overpowered items and pets to fill the void they created by themselves. Typically, they're in the cash shop which creates an even bigger disparity. It seems like most of these people have never even played the game and don't realize how much Master Classes, MC equips, and 6 slot belts broke the game.
Medium rate servers offer a decent compromise and typically sport a better community. Lastly, low-rate servers, at least from my experience, usually don't have a big community unless they're marketed properly since people are incredibly lazy and don't want to work for anything.