According to test result of HTML5 test, the BlackBerry PlayBook performs the best. Based on its powerful hardware and browser rendering technology, PlayBook get the highest score among the released tablet PCs. The figure below shows the result from HTML5Test website.
Mobile Phone HTML5 test results shows MeeGo1.2 rank #1. While BlackBerry OS rank after it.
All these test are based on a premise that iOS 5 is not released.
For your reference, I uploaded the test result of Chrome I’m using now.
As HTML5 becomes more and more popular now, this result is a good news for RIM. Since Apple also don’t support flash, we will see more and more flash app turn to html5.