Thanks to Leopard's many under-the-hood improvements, users can expect to see significant gains in performance and responsiveness under Mac OS X 10.5, especially on recent Macs. Window resizing relative to different System Preference Panes, for example, is now instantaneous and completely smooth, without that half-second delay found in previous Mac OS X releases.
As far as build 9A343 specifically goes, most of the bundled applications and utilities remained unchanged from earlier builds. The Terminal has seen substantial improvements with the first public release of version 2.0; tabbed windows and a new Inspector and preferences are the most notable preferences.
Apple has also added a three new screensavers to Mac OS X 10.5, details of which can be found in the accompanying screenshot gallery.
The launch of Mac OS X Leopard is expected by the end of March.