>IE9 is lots better. Microsoft promised better compliance with IE10, but last I checked, the HTML5 standard wasn't finalized and some browsers are again taking liberties.

HTML5 is still primarily a panacea for people to make promises about how compatible their next web app will be.

Once it ever actually becomes a standard, then I'd expect most browser makers to pick it up cleanly.

>
>>IE9 and 10 (at least what is in Win 8) actually do very well. 8 wasn't too shabby if the page was using strict DOCTYPE.