I just borked my icebook with Duality 4. It reported that the theme was not compatible with my OS (which it is as I'm running it on my tower) and installed it anyway. On reboot the ibook would never get beyond the blank blue screen. Had to reformat and reinstall.

For some reason i seem to have fooked my system more than once with duality but not with other theming apps.

Themechanger seems to be promising though. Hopefully future versions of Duality 4 will be "better".

YMMV