We're using CSS transforms that are supposed to be hardware accelerated but we have a lot of optimization to do to improve the smoothness of transitions.
Crashing may be a memory issue. As you click around,the framework loads the new page with Ajax and adds it to the DOM. We haven't yet implemented a system to only hold X pages in the DOM and dump older ones to keep things tidy. So if you click around, the page will eventually get pretty large.
For now, you can add a rel="external" to links. This tells the framework to do a full page reload and will give you a fresh start. Might make sense to add this to certain links to ensure that the DOM is cleaned up periodically.
We're going to be doing a lot of optimization to improve performance on devices with less horsepower. We've been using a Google G1 as our low-end Android device for testing and see similar issues - slow scrolling, lockups, etc. because of the slow processors and limited memory.
Some of the rendering issues may be that the browser doesn't anti-alias elements with border-radius or cleanly re-size graphics. CSS gradients can be a bit expensive to render too. We'll look into that, but please log any specific issues on the Git tracker for us. http://github.com/jquery/jquery-mobile/issues
Glas you like the direction of the framework. Thanks for all the detailed feedback, we need to hear about all the issues on each platform (they're all quirky) help us improve by logging each at: http://github.com/jquery/jquery-mobile/issues
The toggle switch was working perfectly until Friday, we had a bit of a regression on that one.