I have a 50 shadow and 47 jug.
With that being said before 1.2 I would say the assassin has the advantage, however the 23% boast to ravage really puts the edge slightly in the jugs favor for dps. I've seen veng, rage, and immortal with dps gear all very effective. Immortal with dps gear is similar to tank assassin however I'd say slightly more utility and ravage >> 3 stacks harnessed darkness lightning.
The only advantage for the assassin would be stealth, however the jug gains more damage reduction and more control with very close to same damage. Also Jug can armor debuff their targets.
Long story short - is the utility of stealth worth losing cc, utility, and damage of a jug?
The difference is small though so another way to pick would be by looks, double bladed saber with robes/dress or single saber with robes/pants?