Monk: great defense/high burst/great continuous damage/tons of options

Ninja: ok defense/very mobile/can set up a great burst for party.

Dragoon: good aoe damage/only class that can escape holmgang/great at chasing/ good continuous damage.

Samurai: power house damage/has the best defensive skill in the pvp.

Bard: probably the worst, I'd say wait till 5.1

Mch: great aoe damage/great burst/ good continuous damage/ really squishy tho

Redmage: Jack of all trades/ high survivability and can heal others

Black mage: powerhouse damage/ very mobile. Casting can be rough sometimes.

Summoner: odd to play [imo] great damage but you really have to focus on 1 target. Great burst.

Dancer: no clue but I've seen many do really high damage numbers in the evaluation screen.

All this is just opinions of mine.