If you're developing for iOS, you're probably particularly interested in how iOS handles HTML5.
Even if you love Flash, you might want to think about redirecting some of that affection, given today's news from Adobe.
Good news for iOS developers, though: iOS 5 handles HTML5 really, really well.
In fact, after firing a battery of HTML5 tests at iOS 5, Sencha concluded in no uncertain terms:
Mobile Safari continues to hold the crown as the best mobile browser, providing the best HTML5 developer platform.
That's a pretty ringing endorsement.
HTML5 Canvas is particularly impressive. Sencha's testers report:
In iOS 5, Canvas is between 5x – 8x faster. We tried two examples to see this work. First, the IE HTML5 Speed Reading Test. In iOS 4.x, the draw durations last roughly ~850ms, versus iOS 5, where they are a constant 10ms.
Blaze.io agrees, as this video vividly demonstrates:
WebGL works too -- officially for iAds only, although there is a workaround (but the resulting app can't be listed in the app store).
For more on these upgrades, consider the quick tabular overview of mobile HTML5 support at mobilehtml5.org; read Sencha's discussion of their test results, which concentrate on HTML5; or check out Blaze.io's full performance report, which addresses non-HTML5 improvements too.