[tensor]

I'm very skeptical. Claims like this never seem to be born out in actual benchmarks.

http://pacoup.com/2011/02/03/flash-vs-html5-performance/

http://www.craftymind.com/guimark3/

The advantage of flash right now is that you can be reasonably sure that if a user has it installed, they will get a minimum set of features and performance. With HTML5, your complex app may run fine, or may not run at all, depending on the users implementation.

I've no doubt the performance gap between flash and html5 will continue to narrow. However, I'm less sure that there is anything in the design of html5 that would allow for implementations that are significantly faster than flash allows for. Perhaps someone with deeper technical knowledge of the two could comment.

HTML5 does have the advantage that it's an open platform, of course. Thus you are much more likely to actually see competing implementations of the standard.

[fedorabbit]

I agree. Especially Apple will try to compete heavily on HTML5 standards, since Flash is out of question for iPad, and iPhone. Since their devices only support Safari, HTML5 can certainly be optimized for it. Same thing for the rest of the world... kinda make it more complicated than Flash platform.

[chc]

Not so. I see people all the time who just get a "This content requires a newer version of Flash."

[tensor]

That can happen. Or users may not even have it installed. But contrast with the case of a user with a browser that doesn't support some features of HTML5. How do you detect which features work for them, and which don't? How can the user fix the problem?

The only way to fix it is to install a new browser, or perhaps a new version of the current browser. Installing a plugin is often easier. Rather than deal with this, developers currently just develop for and test on a few main browsers. Anyone not on these are left with no other options but to switch browsers.

Suffice to say, HTML5 doesn't really improve the situation all that much. It simply trades the closed model that Adobe uses with Flash for an open model that has been used for HTML. In either case, the only way to be really compatible is to use older well established features.

Open platforms are good, and thus HTML5 is a good development. But it's not the silver bullet that many make it out to be.