one thing I'd like to scream from the rooftops about Web fonts in IE, though: IE respects the TrueType/OpenType embedding level, but at least some other browsers (last I checked) don't. if your Web fonts are set to an embedding level below "installable", IE will refuse to embed them and use the default font instead. double-check to make sure your font embeds properly in IE 9 before pushing to production.

edit to add: to check, open up the developer tools with F12, go to the console, refresh your page, and make sure you're free of errors like this:

"CSS3114: @font-face failed OpenType embedding permission check. Permission must be Installable. iconic_stroke.otf"

(this error taken from the link in the OP, the icons on which completely fail to render properly in IE 9.)