These are some common issues that you should be aware of. If you're having trouble, you may want to look through these to see if any apply to you or may be the source of your problem.
The solution here is to run the charts using a web server. At this time (March 2010) only Safari, Chrome and Opera support saving annotations when running locally.
Since one of the Chrome 4 dev releases there has been an issue with Google Chrome 4 and 5, asynchronous processing and not rendering chart labels. This has been remedied by simply not using asynchronous processing. Because of the tag placement on the front page, the effect shouldn't be apparent. Other browsers (eg Firefox, Safari, Opera, MSIE) are fine.
Update: Currently, (roughly March 2011), the missing text issue appears to be much less evident, if not resolved entirely.
Firefox, tooltips and using the clipboard is a little convoluted. To copy the text in a tooltip you must do the following:
Note: Recent versions of Firefox 4 (from beta 6 onwards) appear to work as expected, and you can copy text with the mouse as normal.
Shadows in recent versions of Google Chrome are somewhat broken. Firefox, MSIE, Opera and Safari are fine. The reason for this error is a combination of factors it seems - shadow blurring and line width. Fixes have been added to allow shadow blurring and a 1 pixel linewidth, though some chart types may still be affected.