I can't actually decide. Traditional animation has been good in the past, particularly with Animated, but CG has also been used well, as in Beast Wars and Beast Machines. The two have only been really sub-par when they were combined in Energon.

As I see it, 2D drawn animation is good for simple designs, such as in G1 and Animated, and 3D is useful for complex designs which would be hell to draw repeatedly.