Would there be a large improvment in jpeg quality using the E-300 over my Panasonic FZ-20? Not using raw and then converting to jpeg but shooting jpeg and then compare.
The biggest change would *probably* be in ability to crop, since the 8MP of the e-300 gives you quite a bit of extra range over the 5MP of the FZ-20. Sheer picture quality is a fairly subjective thing, though. I would suggest you bring a CF card to your dealer and take some test shots with the e-300 at SHQ resolution, then take the same shots with your FZ-20. That will at least give you a bit of basis for comparison.