While I find some of the experiments at created icons with CSS interesting I wish people would concentrate on testing and pushing SVG for vector images in web pages. SVG is small, fast and well-designed format for rendering static images.
To my taste, a benchmark test like this completely misses the point (even if it includes benchmarks for SVG rendering—which this one doesn't).
It's interesting to see HTML+CSS3 slowly re-implementing SVG in an awkward way.
All the major browser developers are adding hardware acceleration. Creating a suite of tasks to give them a target to shoot at would probably help to solve the performance issue in the next couple of revisions. They made short work of the JavaScript benchmarks and Acid2/Acid3 tests, for example.