.importing svs/pngs animations or making a movie from them and importing it?
Are you hitting speed or reliability issues? How do you define 'effective' ?
If you can provide a bit more detail about what you're asking that would be helpful.
Animating in Hype though would be your best bet I guess. My experience is that these animations are better scalable and offer more copy-paste linience when used in different layouts.
But as Daniel mentions: what is it that you exactly want to do?
performance...if the audience will be able to play content without hickups...im worry that if the animation is too long it would create problems..