Windows/Mac/Linux: Up until now, clearing out your Flash cache or otherwise tweaking its settings required visiting a special web link. With the beta of 10.3, changing your privacy, storage, or other settings is now integrated into your system's Control Panel/System Settings, which is quite handy.
When you think about it, it's somewhat ridiculous that you'd have to open part of Adobe's web site to clear out your Flash cache or adjust microphone/webcam settings. Now you can search out "Flash" in your Control Panel on Windows, Mac, or Linux, and get right to those same settings. The settings will also be baked into the individual browsers—Firefox 4 and Internet Explorer 9, at first—though I didn't see a Flash setting in my Firefox 4 beta right away.
There are a few other improvements in Flash 10.3 beta, including automatic update notifications on Mac OS X and "Acoustic Echo Cancellation" for streaming developers to play with. And if you're sticking with Flash 10.2, you should see an update today that improves HD streaming performance.
Flash 10.3 Beta is a free download for Windows, Mac, and Linux systems.
Download Adobe Flash Player 10.3 beta [Adobe Labs]