I really like the effects created by this plugin. It's easy to do and the shortcode generator is easy to follow. I like the preview that it gives so you see exactly what you'll get. It even shows the actual text you're using!
One important enhancement would be to make it usable in text widgets without adding a link to the style sheet. (See the forum post by Kopyrite that shows how to do that.)
I'd also like to be able to save some of my settings so I don't have to reenter the hex code for colors each time if I want a uniform look.
Some control over things like padding and the ability to position images within the shadow box would be great also.
Thanks again for the nice plugin!