buckworks - 12:08 am on Feb 5, 2009 (gmt 0)

What are the advantages or disadvantages of using Flash banners vs animated GIFs for ad banners?

I'd like to learn more about the pro's and con's of each but I'm not even sure what questions I need to ask here.

Loading speed? Accessibility? Copy protection? Usable in banner rotators? What aspects should I be thinking about?

One specific question: if two banners had the same or very similar look and feel as perceived by users, would the differences in how they're coded have any SEO implications? Does one format please spiders better or worse than the other?