@PatrickB Obviously, you haven't seen what Flash does to my Macbook Pro. So I guess this is where Steve was coming from... if it does it to MBP, imagine what happens to iPad (iPhone).
As to the original poster, HTML5 is OK for simple interfaces but once you get to "real" game development, it could be cumbersome. Keep in mind that a ton of people are stuck at IE9 which has problematic support for HTML5 and (as we found out) WebSockets.
I wouldn't say we're pushing the envelop, but Riftforge is a pretty good example of a game that is well-suited to HTML5. It's turn-based and it doesn't have unit animations (only effect animations):