This is getting silly. It's fantastic that we finally got canvas in Explorer, but people are putting too much weight to one demo designed to highlight one particularly well performing feature (HW accelerated image draw on canvas #).
This has as much significance as Chrome getting ridiculously better results in V8 benchmark [1] compared to all other browsers.
Please go to CanvasDemos [2] or ChromeExperiments [3] and try some third party canvas demos to see how well IE9 fares across wider variety of canvas use cases.
Spoiler alert: it's nowhere near so clear cut performance champion as it may seem from fish and asteroids demos.
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Edit: (#) in practical terms, the biggest benefit would go to use cases like the upcoming Aves JS game engine [4] and FreeCiv JS port [5].
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[1] http://v8.googlecode.com/svn/data/benchmarks/current/run.htm...
[2] http://www.canvasdemos.com/
[3] http://www.chromeexperiments.com/