Well Panther is finally out (early, too! This guy got his) and I must tell you, Panther is amazing! You’ll find Panther to be much, much faster and more streamlined. There is so much to talk about!
If you are the kind of person that likes to upgrade ASAP, you’ll find Panther incredibly useful. I have not run into any software yet that does not work, however some third party extensions may need touch ups.
If you do upgrade or archive and install, be sure to run DiskWarrior first to fix any date or disk issues. Reformatting the disk is the best choice, but you do lose all of your data, so be careful and backup properly.
Panther started out as a ho-hum upgrade, but the speed and Exposé along with all of the polish to Mail, Address Book, etc has made this a worthy upgrade.
Panther is, in a word, Mac OS X Polish.
Welcome to Mac OS X 1.0.