For those guys out there who are thinking that a flash diffuser is going to diffuse the light in such a manner that magically your hard light will become soft, I have bad news. This piece doesn't do it nor is intended to do such a thing. Since you don't change the size of the light, you won't get softer shadows. Its purpose is to actually convert your one-direction-flashgun to a bare-bulb flashgun.
There are a lots of great things you can do with a bare-bulb flash, since the light is spread equally in all directions, which means you're not limited by one direction any more.
The product itself is well built and fits the flashgun just right.
The light color is not shifted at all which is very good, although when you shoot digitally, you can always shoot a grey card first and make the adjustments later if necessary.
On the downside this diffuser swallows light. Comparing the histograms of two same shots (with and without the diffuser, on camera flash, direct illumination) I noticed an almost perfect match at 2 stops difference. I can't tell for other similar products but I've heard this figure is quite common.
The price: bargain! Grab one of this now, you'll need it!