The light has really only got to do two things well: stay in place and provide glare-free light.
The clip mostly works, though it can be dislodged rather easily. The clamp is not a levered-clothespin, but a parallel clamp that doesn't exert a whole lot of pressure when in place. Not a dealbreaker for bedtime readers, but just don't expect to leave this thing in place while walking around the house or transporting in a bag.
The LEDs put out as much light as a decent flashlight. It's not a peaceful, soft glow but a serious task light on a gooseneck. It's bright enough to annoy a spouse... even a spouse that's watching TV. If Belken knocked the lower setting down to about 1/3 its current brightness, it'd be plenty bright for reading the Kindle. The switch is on the lamp head, which itself is pretty small. Flicking the tiny switch with a thumbnail isn't that bad, but it's easy to flick right past the lower setting and end up lighting up the whole bedroom for a second --before switching the thing off by accident (missing the lowest setting, again). By doing this you end up creating a momentary disco effect in the bedroom just trying to get the thing turned on.
Having AAAs instead of coin batteries in the light is a welcome convenience. You're more likely to have AAAs around the house than some little watch battery. Changing the batts is as simple as changing the batts in a TV remote control; there are no little screws contend with. I haven't had it long enough to judge its battery life, though.
But be aware that the using 3xAAAs in a light does add a considerable amount of weight to the top of the Kindle. The concern isn't really with the weight it adds, but the way it affects the balance and ergonomics of the Kindle. I found the I had to hold the Kindle up a bit higher than I was used to. Holding something for an hour or two, you find that a little change can make a big difference. I found I liked clipping the light to the bottom of the Kindle to keep the center of balance low. But, this covers up the space bar and some other keys. The next best thing is to clip it to the side of the Kindle I'm holding, just above the page turn buttons.
Pro:
AAA battery's easily available and simple to replace
2 brightness settings
Flexible head is easily adjustable for glare-free reading
Con:
Too bright. Even on it's dimmer setting, it lights half the bedroom.
Heavy, affects the handling and balance of the Kindle