Bought this for my new Kindle so I can read at night without waking up my OH; does the job perfectly! If anything it's too bright - I have to adjust it so the light doesn't shine back off the screen. Luckily the flexible neck makes this very easy and it's the work of moments to get to a comfortable reading position.
The light is perfectly good for reading normal books at night - although probably better with hardbacks or decent sized paperbacks than slimmer volumes. It's also a great utility light for DIY, model making, crafts or any other situation where you need both hands free.
The clip is clearly specifically designed for the Kindle as it is shaped to fit the device securely without quite overlapping the screen. However, if you use a Kindle case then the light will also clip securely to the open part of the case.
All in all, great little product, very happy with it!