http://ubuntuforums.org/showthread.php?t=732970
Unless you have a dedicated "test" system for this kind of stuff, I would wait until the official Hardy release.
I have three systems to upgrade, a home system on an older laptop, a production laptop workstation, and an old test system. I am more likely to blow away the test system at work first, just to see how the upgrade works. My reasoning is I need that system the least.