pretty much its like (correct me if I'm wrong),
Paladin: Gets a special healing move and can like take reduced damage
Mage: Gets some sort of magic bonus and unique spells
Villain: Gets sneaking bonuses and some other stuff
Warrior: Gets 2 different fighting stances and an ability that reflects damage on the attacker.
Sorry, I know this is terrible and very general, but its what I loosely remember when I did the thing at the observatory.
There like the signs you can be born under in oblivion, it gives bonus stats and abilities to the play style you prefer.