Birds are easier to manage at first beginning, and they do a great job in PvP too (at least starting from 35). Mages require a multitasking approach (to time heal, buffs, debuffs, mana shield, do combo and revives...) but they are the least expensive farmers. Bears are the most difficult to learn, but definitely the funniest (actually underpowered, especially at PvP, but funny anyway). Try all three classes until 30-40 before decide; at the end you will love all of them!