Quote Originally Posted by samsc
what are you trying to do?
standard definition or hi-def?

and how many layers at the same time?

what is the key 'production value' you want to have most of?

is your animation - graphical or filmed live action?
Ultimately I'm looking for the baseline answer to codec performance issues, and I think your list of questions implies that there is no easy baseline. So for the sake of discussion, I'll create an average use scenario:
Standard Def, single layer, graphical content, 800x600, photo-jpeg medium that will perform at 30fps.