The website themaninblue.com published an animation benchmarking to compare HTML5 vs Flash. Here is the initial post: themaninblue.com/writing/perspective/2010/03/22/
What you'll find is that on PCs, Flash Player is faster than HTML5, and that HTML5 is not that bad for basic animations. I wanted to add more information to this benchmark, testing the Flash Player 10.1 on my MAC, and on my Google Phone (Nexus One). I obtain the same experience. Flash Player is much faster, specially with a basic shadow filter. I also tried to launch the Canvas test on my iPhone 3GS.
I also want to point out that benchmarks are really hard to setup, and it's not easy to compare HTML5 and the Flash Player runtime. In this video, when I turn my phone vertically, I can tell that there's a benchmark issue glancing at the size of the dots. A fixed size of the rendering stage would have been more effective and significant.
My message is that for every technology that deals with animation, you need to take care of performances and code optimization. The Flash Player 10.1 runtime has been optimized by the Flash PLayer team for mobile devices. But, as a Flash coder, you also need to take care of AS3 optimization. That's why I invite you to read this white paper: help.adobe.com/en_US/as3/mobile/index.html
Knowing HTML doesn't mean that you'll become a HTML5 expert. I guess you'll also have to take care of code optimization. That's the same with the Flash Platform. This white paper summarizes a lot of tips and tricks to optimize the rendering of your animation, the CPU and Memory consumptions... and then the battery life.
I remind you that Adobe is embracing HTML5 and that Flash is a complement to HTML. The resurrection of development around the HTML standard is good, and Adobe is committed to support it in their new tools, although the productivity and the expressiveness of the Flash Platform remain huge advantages for the Web community. Look at this video that is a preview of Dreamweaver supporting HTML5 canvas. youtube.com/watch?v=0TwGpgFlrAE Nice!!!
Adobe Flash Platform Evangelist
Follow me on twitter: twitter.com/mchaize/