I've never actually sat down at watched MARTHA SPEAKS, but from the promos that I always see tagged to the end of ARTHUR everyday, the animation for that show, to me, seems to go back and forth... there are some moments when it seems stiff, robotic, and limited, but at other times, it actually does look rather smooth and fluid in some sequences... I guess maybe like with traditional hand-drawn animation, Flash animation can vary depending on whatever artists and animators are working on specific episodes.