Raw is of course the most complete saving of data, but a pain to work with, and provides minimal benefit for 98% of your shots. Where it can provide benefit include shots where you might want to change the colour balance, or night shots and shots where you wish to alter exposure or bring out more shadow etc.

Many photographers don't want to give that up and shoot raw. But the disk space/flash cost is quite high -- raw + large superfine jpeg means 4-5 times the disk space.

Now disk space is cheap and getting cheaper, so more often it's about the flash card space. But those are also getting cheaper. So most folks will probably go your way in time.

A slight saving is to shoot raw + a smaller jpeg, but it is only a slight saving. The idea being that once you have identified your "keeper" images you then go back to the raw files to work from them. It would be nice if tools made that easier to do -- catalog, tag and play around with small jpegs, then do a batch command to pull out the raws of those same images.

Jpeg compression artifacts are not a big issue on superfine jpegs. It's the loss of bit depth and a bit of colour info that are key.