I can't wait until the supported browsers are ubiquitous enough to use these exclusively. The animations on the demo page look great!
I'm stuck with Firefox 3.6 on this workstation but it does most of HTML5 just fine so being 'unsupported' for some animation is a surprise.
Mozilla added support recently, and support has been promised in IE10 and the next Opera release. To me, that spells 'web standard'.
Lots of things get promised in IE that don't wind up being very complete, and it'll be quite some time until the IE7/8/9ers fade away.