Facebook, may not yet be an expert source for advice on consumer internet monetization, but when the world’s largest social network talks technology, the industry listens.

So when Facebook CEO Mark Zuckerberg suggested that his company made a mistake in betting on HTML5 and decided to rebuild the Facebook iOS app in response to user criticism about poor experience and performance, a lot of people took note.

But not everyone was convinced that Facebook’s less-than-satisfactory HTML5-based iOS app was the fault of HTML5’s shortcomings. Sencha, maker of one of the most popular HTML5/JavaScript frameworks, was so offended by Facebook’s HTML5 diss that it decided to prove HTML5 wasn’t Facebook’s problem.

In a blog post, two members of Sencha’s engineering team, Jamie Avins and Jacky Nguyen, explained:

We thought to ourselves: HTML5 can’t really be the reason that Facebook’s mobile application was slow. We knew what the browser on modern smart phones was capable of and what kind of rich capabilities HTML5 offered. We saw the latest generation of mobile devices — running at least iOS 5 or Android 4.1 — push ever increasing performance and HTML5 implementation scores. But perhaps most importantly, we’d seen what our customers were building and the amazing things they were creating using HTML5.

Suspecting that Facebook’s mobile development team had take a “website development approach to building an app” — a common mistake according to Avins and Nguyen — Sencha went to work building Fastbook, its version of what Facebook’s HTML5 app could have been and should have been.

The result: if the video comparison posted by Sencha is any indication, an HTML5 app that is not only on par with Facebook’s new and improved native app, but arguably more capable in some areas.

The devil is in the details

So why has Sencha apparently done what Facebook couldn’t? In looking at how Facebook had architected its new app, Avins and Nguyen discovered some surprising flaws, such as the fact that “much of the application was still raw HTML pages.”

Such flaws suggest that Facebook’s mobile development team was not nearly as thoughtful as Avins and Nguyen, who explain in some detail how they addressed certain challenges in building Fastbook. For instance, to improve the performance of the News Feed, Timeline and Stories, they took advantage of a new piece of functionality, the sandbox container.

Where do you want to invest?

For companies that aren’t HTML5 experts, Sencha’s exercise may appear academic. But therein lies an inconvenient truth: building a wonderful native experience usually isn’t easy regardless of the technologies used.

Other companies, like LinkedIn, have built successful and well-received apps using HTML5, so the question isn’t so much “Is HTML5 ready or not?” but rather, “Where does your company want to invest?” Despite the fact that devices are becoming more and more capable, and HTML5’s viability may be growing by the day, for many companies, HTML5 may not be the right path today. But as Sencha has demonstrated, the decision as to what technologies to use is based more on knowledge and resources than the technologies themselves.

In other words, HTML5 is ready — if your organization is ready for HTML5.