The yahoo maps beta is significant because it’s yahoo’s response to google maps. And it chooses to use Flash instead of AJAX, which is receiving a lot of hype right now. So that’s something to think about in terms of the choice between the two. The argument I’ve traditionally heard about not using flash is because it has long load times, user’s not guarenteed to have it, and it might be over kills. But the fact that it loaded up fairly quickly makes me think there’s something more than meets the eye w/ flash.