I don't really know how much this will tell anyone about how this lite 'works,' but here is a photo, taken in a dark room, with the position switch on low, installed on a Kindle 3. You will note the unavoidable drop off from top to bottom. You can also judge, somewhat, how effectively bright the illumination is from the relative brightness seen on the keys at the bottom. There is no appreciable glare, although in certain positions, you can induce glare at your viewing position with any light source.
http://www.pbase.com/mldavis2/image/130092370/original