All of them and their different playing styles. D:
Jack of all trades, master of none. ololo
But seriously, I like playing a Sacrier for battlefield manipulation, tanking, and that awesome skill that lets you deal damage based on missing HP (godly for pure VIT Sacrier, which all of them SHOULD be because they are the only class with 1:2 VIT stat ratio.). I have 260+ HP at Level 12 and will have potential for 2x more HP than any other class.