PWI USED to be good. Packs essentially killed the game (although it wasn't all bad at first; it got worse when they brought out 4370423702384 different kinds of packs). They brought out 4 new classes and completely disregarded balance, and now with r9r3 running around, and made easier to obtain seemingly with every major content update, unless you spend thousands of dollars, you're never gonna catch up to those who've been around longer or who has a fatter wallet.
EPW is possibly the most balanced p. server out there now. There is no rank 9, only rank 8 recast, but everything is still easy to obtain. And at the end, everyone is equal for the most part.