You obviously must have played for about 5 minutes.
If you mean it was similar to WoW in that both games objectives are to kill monsters, do quests, get items, and level up. LIKE EVERY MMORPG EVER MADE IN THE WORLD, EVER. Then yes, its like WoW. Apart from that, this game couldn't be more dissimilar to wow.
Best class is obviously your own opinion. Slayer and Sorcerers are most high powered classes. Lancer is fun original class. Zerker, priest, mystic, warrior are standard.
Theres a free 7 day trial going on atm. Not sure how many keys are left.