Safari 5.1 / Chrome 12 - must set boxShadowBlur to 200px to match 50px of blur set in CSS (Firefox 3.6 is fine, blur set in JS matches what is set in CSS)
Firefox 6 beta (and sounds like down to v4) doesn't work at all, Opera 11.50 also doesn't seem to work
Little test case: http://hellobold.com/project-inquiry/