Interesting, but I've never really "gotten" this thing with tiny flash diffusers. I mean, if you're serious about getting even, open lighting, there's no getting around the physics of it. You need a larger apparent light source, which means something like an umbrella, softbox, or large reflector to bounce your flash off of. Yes, you can modestly increase the apparent size of the light source with a little diffuser gadget, but most of the benefit is derived from bouncing the resulting light off the ceiling or wall, rather than the gadget itself.
You'll get a lot more bang for your buck by spending $50-$80 on an inexpensive umbrella and lightstand.