We already know Microsoft has to play catch up with WPF/E against Flash. Adobe is basically leveraging their existing technologies to create Apollo. Adobe has already had standalone flash applications for quite a while, it just looks like they are expanding the developer tools to allow that to be done in an easier and richer way. At least that's what it looks like to me. There is one thing that bothers me that I read in one of the overviews:
"One thing Apollo will do, if it catches on: Help bury the myth once and for all that PDF is just a static, electronic photocopy of a paper document. "
Soooo, what do I do if I want a static electronic photocopy of a paper document? I hope Microsoft keeps XPS slim and lightweight. Adobe has tried to pack too much into PDF and that has been bothering me for quite some time.