I play both Bladedancer and Sunbreaker, and Bladedancer is far easier to get kills with. As a Bladedancer, you don't have to think of the arching trajectory and the travel time, your hits always land every time and they home in (you can even fly up in the sky to hit people), you can prolong the duration of the super with kills, you can send out a ranged blast just as powerful as FoH. You can't hide from a Bladedancer, but you can always hide from a Sunbreaker.