[kezza]

I have a Kandle and it clips perfectly and securely to my nook Touch (with or without a case.) I'm not sure how much security you're talking about, do you need to hold the book by the light? The Lyra clip is a little tighter, but both clip securely to the nook body and don't move around.
I find the Kandle has better, more even light than regular "spot" style book lights. I have the Lyra light and don't like it, too much glare and the light isn't even. Two big thumbs up to the Kandle. The only thing I've used that's better was the Lightwedge for my old Sony. Too bad those won't work with the nook touch . . .
Also, I've had my Kandle for over a year and it still works perfectly. Because it has two bulbs, though, it tends to go through batteries a little faster than a light that takes AAAs (it takes 2032 size "coin" batteries). The flip side of that is it's quite a bit more compact and lightweight.