humans:
Knight = slow lvling, hard to kill you, hard to kill anybody
Mage = fast lvling, the highest dmg in game, low defence
Archer = average lvling, best at pvp till lvl 60-70, mana problems from there
Orcs:
Berserker = fast lvling, not very good at pvp
Sorceror = very fast lvling, bad at pvp till you get very high lvl (75+) low defence at low lvls (till lvl 40+)
Hunter = fast lvling, good defence, decent damage
Moonelves:
Ranger = average lvling, good at pvp, hard to kill from lvl 70+
Elementalist = very fast lvling, good at pvp at low lvls, low defence
i'd say that the easyest class for a new player is orc berserker
and the hardest is mage (the hardest if you dont know how to play them), and other casting classes (sorceror, elementalist)
EVERYTHING depends on that, weaps, armors, skill build everything..
edit:
as mentioned here above in my opinion knight is best, but pve only(most hp of all)
pvp he sucks, he might be invinseble(tanker) but in that case u wont be able to kill annyone,
but as knight u can go critical build(DamageDealer).. wich will make u do a lot of crits and therefor dmg, but u are more vunerable..