Out of the camera, I can't detect any visible difference between large fine jpg and RAW extracted in 8 bit format. However, depending on the extraction software used, it is possible to acheive greater highlight detail using 16 bit extraction from the RAW file. Further more, RAW allows exposure and colour adjustments to be applied after the picture has been taken - likewise sharpening allowing scope for experimentation without image degradation.
Finally, with people like Chris Breeze and Fred Miranda dedicating vast effort into extracting the ultimate image from the Canon output, it is not inconceivable that a method of getting even higher quality images from the RAW file will become available in the future - so archiving shots in RAW has some merit.
Colin K. Work, Pixstel