my experience with raw on my 20D is it does produce fewer artifacts... but the Canon proprietary raw format is quite annoying
my sony was able to record in .tif format (well, it wasnt a true raw... it was a jpg converted into the .tif... which meant it was pointless) but recording in .CR2 format requires the proprietary software the camera came with... which is good; but not as useful as PS. PS doesn't recognize the image format.... so i had the files converted from .CR2>.tif
i was then able to do the proper image processing with no quality loss... the strange thing is, the .cr2's were 1/2 the recorded size of the .tif files.
mabey its just that my old version of PS doesnt support CR2's, and PS 8 does?