The disappointing thing is how poorly executed the idea is. For some reason, the designers decided to have them mount to the top of the GBA, not only blocking the link cable socket, but also giving you no place to mount a light. After all, who needs to see the screen if you have great sound? When I first saw that it mounted to the top I figured it fed off the GBA power supply, so I was surprised to see there wasn't at least a pass through. You can fix this problem by just plugging the cord into the earphone jack, but then it looks silly and you don't get quite the same effect as you would mounting them.
In addition, the box fails to mention that you need two AAA batteries to work the thing. Since AAA batteries are not commonly found around the house, (at least every house I have lived in) I can see a few irritated parents.
Audiophiles with great overhead lighting will love the Twin Kickers. The rest of the gaming public would probably do best to steer clear. Personally, I would rather see my games.