Installing new version of OS X


I'm tinkering to try getting various things running under OS X PB and xwindows. As well as other third party software.

I'm getting nervous about the upcoming change to the real OS X ver. 1.

For one thing, since I have everything under OS X in a single partition it's perhaps impossible (read: too much work) to hide it away when the real stuff finally arrives.

You guys who have tried the new builds: Does the installer in the later builds install nicely on top of the old versions, keeping directories such as /usr/local et al.? -- or (heaven forbid) will the installer just clean the tab. Like, erase all this cool stuff that I've downladed?