Chances are, if your current Mac runs Mac OS X "Jaguar" 10.2.6 well, your Mac will be able to run Panther 10.3 just as well, if not a bit better. Did that answer some of your question, keeping in mind you were wondering if it would run on your current Mac? (no, I'm not running the developer version of 10.3 Panther.)
Panther is PDQ for iLifestyle stuff, opening files and windows. Much better navigation.
Serious bugs with Photoshop, Illustrator and Compositor dialog boxes making many filter operations useless.
The bad bug I have with a useless startup disk function in Jag is gone.