ShootSmarter.com have published a comparative review of several devices that modify the output from a flashgun, including the Sto-Fen Omnibounce and the LumiQuest #54-23, from a digital camera point of view:

“Gone are the days where you pull your flash out of your camera bag and point it directly at your subject and fire away. With digital capture your old straight ahead strobe setup will create spectral highlights that your digital camera chip cannot handle. By that I mean your highlights will be blown out and be completely void of detail. This is not what the bride ordered when she hired you the professional photographer or what she saw in her sister?s album when you were still shooting film. A light modifier will soften the quality of your strobe and produce a flatter, more even lighting that will now fit your digital camera?s short dynamic exposure range.”

Website: ShootSmarter.com - Digital Light Modifiers for On-Camera Flash