Mozilla continues to iron out bugs and tweak the underlying code of its upcoming Firefox 4 browser, and if you want to see where things are at, you can now download Firefox 4 beta 10. This 10th beta focuses mainly on stability and includes the following handful of changes:
Compatibility and stability improvements when using Adobe Flash on Mac OS X
Improvements in memory usage
Support for a graphics driver blacklist to improve stability
See here for a complete list of changes and bug fixes since the last beta, and if you're brand new to Firefox 4, see here for the complete feature-set.