I did an archive and install on my Blue & White (upgraded to a G4/500). No major system problems and all my settings appear to have been transfered properly. All my apps run without requiring registration or reinstallation - that is, the ones that actually work in Panther. So far my problems are:

1. FontAgent Pro - takes FOREVER to load compared to under Jaguar, plus theres some interface glitches and i can't seem to hide the window at all.
2. Orange Micro SCSI +Serial Card - the kernel extension just gives an error when I boot up, so no access to my SCSI burner.
3. Small problem with DreamweaverMX 2004 but a quick trip to the Macromedia Forums solved that.
4. Norton Utilities 7 is a no go (is 8 a no go too?). I think I might dump Norton.

Things I like:
1. Speed increase almost all around - menus pop open instantly, apps load quicker, dialog boxes are fast
2. Mail - keeps getting better, opens REALLY fast and doesn't lag like in Jaguar
3. New Finder - very cool!