Lets start with the design/design quality:
The housing is a very poorly constructed plastic and the button is chromed plastic.
The functionality of the unit:
To turn it on, you have to hold the button. You might as well buy one of those keychain flashlights. At least with those, there's a switch.
The lighting is extremely dim and it emits a blueish light in your photos. (you'll need to get to at least 7 inches to have a decent amount of lighting).
The package contents:
Crapply made lanyard, warranty card, instructions, adhesive sticker, and the flash light unit.
NONE! Its one of the crappiest accessories ever! If someone gifts this to you, you'll know that he/she really dislikes you.
-Poor quality material.
-Poor quality construction.
If you really need a light source for your Hero's camera, then you should really get a nice pen light such as the 4Sevens Preon. You'll get higher lumens and its far more versatile/portable than this crappy ViaTek Cell Flash. Plus, with the Preon, you'll get a correct white balance.
There's a reason why this item was premiered on "As Seen on TV". Most, if not all of the products there are garbage and a waste of resources.
Btw, the pictures of the package and the unit were taken from a Sony MHS-FS3. The pic of the $20 were taken by the Hero. No images have been Photoshopped.
Here's some pics (click images for larger pictures):