On the first stages of the game it is easier to go with dueling, but in the middle of the game, there are no great advantage of it.
If you like to use flurry or you are going to be a weapon master jedi, then it is better to have two weapons (or two-bladed lightsaber).
If you are a consule, you may think not to take them at all, because you can choose feats very rare.
Well, about moves. I think that flurry is the best. You see, powerfull attack's bonus of damage +10 isn't big against your's 50-60 usual damage in the middle of the game. Critical hit is usefull, but very rare. But flurry... Master Force Speed + Two-bladed + Flurry = 5 hits. 50*5=250!!! It is a great damage.
And also think about prestige class. If you will be a weapon master, than you must know about 3 additional feats of two-weapon mastery, which can be used only if you have got all 3 usual feats. When you will have all 6 of them, you'll be a great warrior!