Well, it's not only about style. IE9 adds rounded corners but still skips a lot of modern features in HTML5 that simply can't be used reliably by anyone due to IE not supporting them. IE is like a over-turned transport truck across 3 lanes of the highway to a better web. They cleaned up some of the spillage, but... well we're still not going anywhere :)

Styling is the most obvious issue, but it's just the surface of the problem.