The best WoW private server is: [ Register or Signin to view external links. ]

Its on patch 3.3.5a, yea it may not be cata yet but thats because cata patches are way to buggy and they like the server to be near bug free.
There are 5 realms: Neltharion (X12 xp and gold rate) Deathwing (same as Netharion) Sargeras (X20 xp and gold rate) Frostwolf (X3 xp and gold rate without vote and donation rewards i.e. most blizz like) and Warsong (pure pvp with instant level 80 and shops to buy gear)
The server has a vote and donation system to get items fast (without grinding for them) or items you cant get on the server.

3 realms have a player cap of 3750 at a time with a queue that can go in to the 1000's (donate to by pass the queue) the other 2 realms have a cap of 3500

Most realms are full with big queue's in peak time and on weekends which means there are alot of guilds, raids and other stuff going on

So come on join and see the server for your self happy gaming