Paladins are a very fun class. If you like serious, competent PvP then Ninja would be a better choice. However, if you play a Paladin there's still a whole game to enjoy along with PvP so don't let it ruin it for you. You can counteract the overpowered nature of Paladins somewhat by not locking.
Destroyers are a great class and are fun for PvP but I would make the claim they are for the moderately skilled Dragon Saga players. Typically, out of a weird habit, people always end up making Destroyers as their alt character. They're extremely fun but tough to master.
Ninjas are very fun for beginners, have great skills and really diverse PvP tactics. If you play a Ninja expect to be held to a standard of greatness if you want to fit in. I would recommend you be a Ninja out of these three especially if you're new. Keep in mind that Ninjas will have a very reaction-based nature in later PvP and that it's probably one of the more challenging but more rewarding PvP classes.
As far as leveling these three goes, Destroyer would also be the most difficult to level up. Ninja would be the easiest, with Paladin in the middle.
Edited by Kazu731, 06 July 2011 - 08:19 AM.